Nonnuclear Industrial Hazardous Waste:Classifying for Hazard Management

November 1981

NTIS order #PB82-134305

Library of Congress Catalog Card Number 81-600170

For sale by the Superintendent of Documents,U.S. Government Printing Office, Washington, D.C. 20402

Preface

The Office of Technology Assessment is currently conducting an assessment onnonnuclear industrial hazardous waste at the request of the House Committee on Ener-gy and Commerce. Its Chairman, Rep. John D. Dingell, asked OTA for a preliminaryreport on hazard classification because this critical issue, one of several being studied inthe OTA project, will likely be addressed this fall.

This technical memorandum addresses the following topics:

● basic issues surrounding a degree-of-hazard classification approach; the potential for incorporating a degree-of-hazard concept through classifica-

tion in current regulations of the Resource Conservation and Recovery Act(RCRA);

● various ‘methods for applying a degree-of-hazard classification system; and some questions to be addressed in making the decision whether or not to select

and incorporate a degree-of-hazard classification system at the Federal andState level.

OTA’s analysis to date finds that a well-designed degree-of-hazard classificationsystem might provide a strategy for cost-effective management of nonnuclear industrialhazardous waste, However, it would be important to choose several degrees of hazard-ousness and not to exclude types of waste, such as those generated in relatively smallquantities and some chemicals with known chronic (long-term) toxicity, without mak-ing assessments of the levels of hazard they pose to the public.

While a regulatory system based on degree-of-hazard classification may appearreasonable and cost effective, it should not be regarded as a panacea for the critical na-tional problem posed by industrial waste. Moreover, it is not necessarily a radicaldeparture from existing regulations. No change in RCRA would be needed, and aquantitative hazard classification scheme could be incorporated incrementally intovarious segments of the current program. Hazard classification, based on scientific datafor waste, management technologies and sites, should be viewed as an evolutionaryrather than revolutionary development for industrial waste management and regula-tion.

Nonnuclear Industrial Hazardous Waste Advisory Panel

Myron Tribus, Chairman’Massachusetts Institute of Technology

David AndersonBethlehem Steel Corp.

Frank CollinsOil, Chemical and Atomic Workers

International Union

Jeffrey DiverWaste Management, Inc.

Phillippa FootUniversity of California, Los Angeles

Thomas H. GoodgameWhirlpool Corp.

Diane GravesSierra Club

Sam GusmanConservation Foundation

Rolf HartungUniversity of Michigan

Robert L. JuddState of California

Kenneth S. KamletNational Wildlife Federation

Terry LashKeystone Center

“Resigned as of Aug. 21, 1981.● *Resigned as of Sept. 24, 1981

David LenettEnvironmental Defense Fund

Joe J. MayhewChemical Manufacturers Association

John M. MulveyPrinceton University

Steven J. PiccoState of New Jersey

Delbert RectorState of Michigan

Gerard A. RohlichUniversity of Texas, Austin

Kenneth J. Rothman**Harvard School of Public Health

Reva RubensteinNational Solid Waste Management

Association

W. Earl TatumE.I. du Pent de Nemours & Co.

George M. WoodwellMarine Biological Laboratory, Woods Hole

NOTE: The advisory panel provided advice and critique, but does not necessarily approve, disapprove, or endorse this tech-nical memorandum for which OTA assumes full responsibility.

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Nonnuclear Industrial Hazardous Waste Project Staff

Lionel S. Johns, Assistant Director, OTAEnergy, Materials, and International Security Division

Audrey Buyrn, Materials Program Manager

Joel S. Hirschhorn, Project Director

Suellen Pirages, Senior Analyst

Iris Goodman, Research Assistant

Michael Gough, Consultant (OTA Health Program)

Administrative Staff

Carol A. Drohan Patricia A. Canavan

Contractor

Sterling Hobe Corp.

OTA Publishing Staff

John C. Holmes, Publishing Officer

John Bergling Kathie S. Boss Debra M. Datcher Joe Henson

Acknowledgments

The following also provided considerable assistance in the review of various drafts of thismemorandum:

S. Daniels, Dow Chemical Co. G. Hurlbert, State of Michigan

H. Yakowitz, National Bureau of Standards H. A. Caves, State of Oklahoma

B. Simonsen, IT Corp. E. Falk, Union Carbide Corp.

E. Tower, State of Washington J. Carmichael, State of Texas

S. Barkin, National Materials Advisory Board H. A. Wray Associates

C. Perket, Environmental Engineer and W. H. Prior, Kaiser Aluminum, Inc.Management Ltd.

ContentsPage

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Concept of Degree of Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Technical Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Degree of Hazard Concept v. Hazard Classification. . . . . . . . . . . . . . . . . 10

Objective and Purpose of a Classification System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Economic Effectiveness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Uncertainties in Implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Degree of Hazard in the Current Regulatory Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Methods for Classifying Waste and Facilities by Degree of Hazard. . . . . . . . . . . . . . . . . . . . . . . . . 17Classification Using Technical Criteria. . . . . . . . . . . . . . . . . . . . . . . . . . . 17Rank-Order Classifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Multiple Discriminators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Classification by Environmental Containment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Unresolved Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Appendix: Dangerous Waste Criteria for the State of Washington . . . . . . . . . . . . . . . . . . . . . 33

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

List of Tables

Table No. Page1.2.3.4.5.6.7.8.9.

10.11.

A-1.

List

Toxic Doses for Selected Hazardous Waste Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Selected Examples of a Degree-of-Hazard Interpretation in Current RCRA Regulations. . . 15Toxicity Criteria in the California System of Degree-of-Hazard Classification. . . . . . . 18Criteria for the Texas System of Degree-of-Hazard Classification. . . . . . . . . . . . . . . . . . . . . . . 19Criteria for the Washington System of Degree-of-Hazard Classification. . . . . . . . . . . . . . . . . . 20Proposed Technical Criteria for Classifying Nonnuclear Industrial Hazardous Waste. . . . . 21Comparison of Proposed Degree-of-Hazard Classification Systems. . . . . . . . . . . . . . . . . . . . . 21Michigan’s System for Rank-Order Assessment of Critical Materials. . . . . . . . . . . . . . . . . . . . 23Suggested Effect and Exposure Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Suggested Environmental Parameters for Classifying Facility Sites. . . . . . . . 25Potential Classification Scheme Based on Containment and Destruction. . . . . . . . . 26Toxic Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

of Figures

1.—

2.3.

4.

A-I

Information and Decision Flow for Current and Alternative Waste Management . . . . . . . . 7Factors of Importance to Degree-of-Hazard Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Decision Analysis Illustrating the Impact of Degree of Hazard on the Choice ofManagement Practice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Research, Development, and Analysis Requirements and Possible Benefits ofImplementation of a Hazard Classification System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Toxic Dangerous Waste Mixtures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Summary

The management, or in some cases misman-agement, of industrial waste present variouslevels of hazard to the public. Nonnuclear indus-trial waste range from being relatively harmlessto being so extremely hazardous that the wastemust be totally isolated from humans and theenvironment, destroyed or permanently detox-ified. In developing regulations to implement theResource Conservation and Recovery Act of1976 (RCRA), the Environmental protectionAgency (EPA) chose not to classify wastebeyond a designation of hazardous or nonhaz-ardous. Moreover, EPA has excluded types ofwaste, such as those generated in relatively smallquantities and some chemicals with knownchronic (long-term) toxicity, without making as-sessments of the levels of hazard they present tothe public. The Office of Technology Assess-ment finds that a well-designed degree-of-hazardclassification system might provide a strategyfor cost-effective management of nonnuclear in-dustrial waste. A quantitative classification sys-tem incorporating the degree-of-hazard conceptis possible because the following two conditionsare met:

● particular waste, management programs,and sites have important shared characteris-tics; and

scientific criteria and data that describe haz-ards are either available or can be, in prin-ciple, obtained.

Alternatively, a qualitative degree-of-hazard ap-proach without specific categories requires lesseffort to develop criteria and data, and its ap-parent simplicity may be attractive from a pro-grammatic perspective. In the long term, such anapproach could prove to be inefficient, sincescientific information appropriate for classifica-tion may be needed in the future. In addition,much of the information obtained in a quali-tative approach on a case-by-case basis often isnot fully used, may be unnecessary, and often isnot appropriate for classification.

The present state of knowledge, however,does not lead to an easy endorsement or con-demnation of the use of a hazard classification

system for implementing the mandates ofRCRA. While a system based on degree of haz-ard may appear reasonable and cost effective,degree-of-hazard classification should not beregarded as a panacea for the national problemposed by disposal of nonnuclear industrial haz-ardous waste. Moreover, it is not necessarily aradical departure from existing regulations.Classification by hazard could be incorporatedincrementally into various segments of the cur-rent program. Hazard classification should beviewed as an evolutionary rather than revolu-tionary development for industrial waste man-agement.

The objectives of a classification system aretwofold:

to identify with greater certainty industrialwaste that pose the most severe threats tohuman health and environment; and

● to allow development of management strat-egies that reflect the differences in potentialhazards of industrial waste.

Waste classification methods include technicalcriteria based on waste characteristics, rank-ordering based on results of specified tests,grouping by particularly important character-istics (multiple discriminatory factors), and or-dering the potential of facilities to contain or de-stroy the waste. Because of incomplete infor-mation and data about industrial waste streams,none of these methods can be implemented with-out first developing scientifically based criteriathat reflect both real world exposures and intrin-sic properties of waste. Although much of thepreliminary investigative effort required to de-velop a degree-of-hazard classification systemhas been initiated in compliance with other envi-ronmental regulations, further evaluation of allschemes is needed.

The benefits of using degree-of-hazard classifi-cation in regulating industrial waste include con-centration of regulatory action on waste thatpose the greatest hazards; a more effectiveallocation of the resources of generators, dis-posers, and government; a means to establish

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priorities for reduction of the waste stream bychanging manufacturing processes, end productsubstitution or recycling of waste; a means to in-crease the public’s knowledge about the varia-tion in hazard posed by industrial waste; andfinally a means to assure that the intent ofRCRA is achieved.

A number of questions, however, require ex-amination. There is concern about the costs toEPA for developing a classification system, and

also the cost to society for time that might belost during a transitional period in implementa-tion of RCRA. Uncertainties surround availabil-ity of appropriate data, the ability to establishscientifically based criteria, and increased com-plexity of regulations. Finally, the costs thatresult both from developing a degree-of-hazardsystem and from not designing a classificationapproach need to be determined.

Background

The concept of degree of hazard is receivingincreased attention as discussion of the currentsystem for regulating nonnuclear industrial haz-ardous waste (NIHW) continues. For example, ithas been reported that the Executive Office ofManagement and Budget has requested the Envi-ronmental Protection Agency (EPA) to conducta review of the Resource Conservation and Re-covery Act (RCRA) regulations; this review mayinclude a study of the potential for incorporatingreferences to the degree of hazard of variouswaste. (1) Moreover, the House Committee onScience and Technology has identified classifi-cation of hazardous waste as a major issue.(2)

There appears to be no question among thosewho deal with the issue that there are differingdegrees of hazard and that different means ofhandling treatment disposal are warranted.The problem is in applying degrees of hazard tospecific wastes. Both economically and from anenvironmental and health standpoint, the issueis legitimate,

Because of the complexity of industrial waste, itdoes not seem appropriate, however, to refer-ence or consider degree of hazard without un-derstanding the meaning of the concept, thenecessity of establishing technical criteria forclassifying waste, and the problems surroundingimplementation of a classification system in Fed-eral and subsequent State hazardous waste regu-lations. A discussion of each area is presented inthis document.

As part of a comprehensive, ongoing assess-ment of nonnuclear industrial waste, OTA isstudying the potential application of a degree-of-hazard concept to regulatory policies. For thepurposes of this report, degree of hazard reflectsthe relative level of particular characteristicsselected by EPA for defining a hazardous waste(i.e., toxicity, ignitability, corrosivity, and reac-tivity). Risk assessment, in contrast, estimatesthe probability of adverse impacts resultingfrom a hazard during particular exposure condi-tions. Risk analysis estimates the social and eco-nomic costs that would result from a particularlevel of risk. This document is limited to a dis-

cussion of a degree-of-hazard system as a meansto reduce risks posed by management of NIHW.

The first phase of the OTA study is a reviewof the methodology that might be adapted foruse in classifying and managing industrial waste.Subsequent phases will explore unresolved ques-tions that have been raised at this stage of the as-sessment and will analyze further the feasibilityof implementing a degree-of-hazard conceptwithin the current regulatory structure. As ameans of providing a basis for understanding theconcept and potential benefits as well as antic-ipated problems, this paper discusses thefollowing:

basic issues surrounding a degree-of-hazardclassification approach;the potential for incorporating a degree-of-hazard concept through classification incurrent regulations;various methods for applying a degree-of-hazard classification system; andsome questions to be addressed before thedecision whether or not to select and incor-porate a degree-of-hazard classification sys-tem at the Federal and State level can bemade.

RCRA was enacted, in part, to regulate themanagement of hazardous waste.(3) Regulationof NIHW, however, is a complex problem. Thetypes of waste that must be regulated consist ofdiscarded byproducts from industrial produc-tion processes and residues created by commer-cial use of industrial compounds. These include,for example, wastewater sludges from a varietyof processes, organic chemical residues, spent-plating bath solutions from electroplating proc-esses, and emission-control dust/sludges fromsecondary lead smelting, The chemical, phys-ical, and toxicological properties of these NIHWare quite diverse and produce effects on humanhealth and the environment that vary in char-acter and severity. Because industrial waste gen-erally comprise mixtures of compounds, oftenthere is uncertainty surrounding the specificityof cause and effect relationships between the

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presence of a hazardous waste and a perceivedadverse impact. This diversity (in types ofwaste, their properties and effects) and lack ofcertainty present a challenge for designers andenforcers of Federal environmental policies tofind a regulatory structure that is cost effective,capable of being implemented on a nationallevel, and compatible with the variety of NIHWbeing generated as well as the diversity of envi-ronmental conditions.

The legislative history of RCRA suggests thatCongress was aware of the complex nature ofNIHW and was concerned with appropriateways to identify waste that present the most haz-ard to human health and the environment. Pre-liminary discussions centered on such issues asvolumes of the waste being considered and thecertainty, or lack thereof, of identifying adverseeffects. For example, the following observationwas made in a congressional committeereport .(4)

The Committee anticipates the identificationof two basic types of substances: those whichare hazardous in their elemental and most com-mon form, regardless of concentration, andthose which when present in sufficient concen-tration or when mixed with other substancesconstitute hazardous waste. The criteria foridentification of these substances should makesuch a distinction based on the danger to humanhealth and the environment. The listing of anysubstances not found to be hazardous per seshould be accompanied by an explanation as towhen such waste are considered hazardous.

Some members of Congress suggested that theact should make reference to regulating NIHWaccording to the extent to which waste pose ahealth or environmental threat. In subsequentdiscussions on amendments to the act however,Sen. Jennings Randolph, one of the key sponsorsof RCRA, maintained:

. . . that flexibility can be accomplished withinthe current agency consideration of the pro-posed regulations and the comments received ina manner consistent with the statute.(5)

The final act neither requires nor precludes thedevelopment of a regulatory system based onclassifying NIHW by the potential to cause harmif managed improperly.(6)

In developing regulations to implement theRCRA mandate, EPA chose not to classify wastebeyond a designation of hazardous or nonhaz-ardous. The Agency’s position was taken fortwo reasons.(6)

The Agency does not believe that any of thedegree-of-hazard systems suggested by com-mentors (or any the Agency could itself con-ceive) are capable of actually distinquishingdifferent degrees of hazard among the myriadhazardous wastes and also reasonably relatingmanagement standards to these degrees in atechnically and legally defensible way. . . (and)believes that the final regulations alreadyachieve the objectives of a degree-of-hazardsystem; thus such a potentially complex andchallengeable system is unnecessary.

Comments received by EPA on the December1978 publication of the first set of proposed reg-ulations, however, suggest that regulatingNIHW according to degrees of hazard could be acost-effective strategy.(7) Several arguments forthis type of system have been presented.(8) First,the use of a degree-of-hazard approach concen-trates regulatory action on waste that exhibit ahigh level of hazard and have the greatest prob-ability for exposure to humans and other organ-isms. A degree-of-hazard system could preventexcessive regulation of waste shown to presenteither a low hazard potential or a low prob-ability of exposure. Moreover, although there isgeneral recognition of the need to reduce wastegeneration at the source, through such measuresas process or end-product change, without someclassification of waste it is difficult to establishappropriate priorities and goals for wastereduction.

Second, the volume of waste to be handled byprocedures outlined in the regulations is antic-ipated to be quite large; EPA estimated thatNIHW generated in 1980 could range from 28million to 56 million metric tons with annual in-creases of 3.5 percent expected .(9,10) A systemof classifying waste by degree of hazard couldfacilitate effective management programs byconcentrating limited resources of generators,disposers, and government on those materials ofgreatest concern. For example, there are a lim-ited number of appropriate sites where waste

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can be disposed safely in land (i. e., with minimalcontamination of surface or ground water).Given this limited availability, it is suggestedthat a management policy should be developedwhereby the most hazardous waste are de-stroyed, detoxified, or as a last option sent to themost secure land disposal sites, and the less haz-ardous materials are assigned to sites requiringfewer controls and lower management costs.Analyses and forecasts of landfill capacities on aNational, State, or regional basis are likely to bemade more accurate and useful if hazard classi-fication becomes used.

Finally, a degree-of-hazard approach to wastemanagement could be used to direct educationalefforts toward increasing the public’s under-standing of those properties of waste and envi-ronmental conditions that contribute to con-tamination problems. While the public hasbecome increasingly aware of dangers associatedwith disposal of NIHW, this awareness has beenaccompanied by misunderstandings about thediversity of hazards posed by different types ofmaterials. This lack of understanding is due inpart to limited access by the public to the avail-able information about the expected threats tohealth or the environment. As the public be-comes more knowledgeable about differences inhazard posed by the variety of NIHW, greateracceptance of waste treatment or disposal sitesmight result for low-hazard waste sites and forhigh-hazard waste sites that reflect the most ap-propriate and safe management. It can be ar-gued, however, that as the public learns moreabout specific waste and dangers they pose, de-veloping a necessary consensus on siting couldbe delayed.

More recently, some concern has been ex-pressed that the current regulations of EPAcould eventually undermine the intent of RCRAby allowing some potentially hazardous wasteto escape regulation.(n) For example, it hasbeen suggested that the listing mechanism foridentifying hazardous waste reduces the efficacyof the act. The current EPA list is considered bysome to be deficient with initial exclusions ofmany hazardous materials and the potential toremove identified hazardous waste from the list.Because of a failure to establish clear criteria,

certain types of exclusions in current regulationscould reduce the effectiveness of RCRA, particu-larly in the long term. These exclusions includesmall generator exemptions, materials coveredunder other environmental regulations (e. g.,Clean Water Act), specific exemptions of mate-rials through the delisting-petition process, andthe potential to designate a hazardous materiaIfor recycling purposes and therefore removing itfrom regulatory control.

Arguments can be made that it would be moreprudent to provide an all-inclusive regulatorypolicy with established criteria rather than onewhich allows a variety of exclusions. For exam-ple, the policy might be to classify all industrialwaste and not to exclude any from some level ofregulation (i. e., using permit by rule for less ornonhazardous waste). An aura of uncertainty iscreated when the potential exists at some futuretime to relist waste currently exempted and de-list waste currently included. A degree-of-haz-ard approach based on classifying and regulatingall industrial waste could facilitate private sectorinvestment decisions for waste management fa-cilities by providing a more certain regulatoryenvironment and could shift the current reg-ulatory emphasis from the legal to more tech-nological arenas.

The format for applying a degree-of-hazardclassification system, however, would have tobe designed carefully. A very complex systemmight be unworkable and unmanageable. A sys-tem using three to four broad classes of hazard(e.g. high, medium, low, and nonhazardous)with specific criteria for each could provide areasonable regulatory framework. Such a sys-tem could include the disposition of all industrialwaste including small quantities, specific less-hazardous waste with their related liabilityneeds, material covered under other regulations,and waste designated for recycle or reuse.

Included in the comments on the 1978 pro-posed regulations were several proposals forclassifying both waste and management facilitiesby the degree of hazard posed to human healthor the environment. After review of thesesystems, EPA determined that a satisfactoryclassification scheme could not be readily de-veloped nor implemented within the time period

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mandated by Congress. EPA was under a court-ordered schedule to develop Federal regulations.EPA was already late in meeting the scheduleand pressed to develop a program quickly. EPAfelt that the objectives of a classification systemcould be met just as efficiently through a phasedapproach in promulgating regulations. For ex-ample, the initial list of NIHW included thosewhich EPA considered to pose the highest riskand for which the most information on healthand environmental impacts was available. EPAintended to add other waste to the list over time.In addition, the first set of proposed regulationsincluded exclusion levels for small quantities ofwaste, a variance procedure allowing disposersto demonstrate that the level of required in-surance was not consistent with the degree ofrisks associated with their facility, and peing procedures for requesting lower levelssurance. Also, in this first phase of regudevelopment, EPA stated the intent to

ition-of in-a torytailor

management requirements reflecting differencesin potential hazards of NIHW as well as dif-ferences in environmental conditions surround-ing the facility site.

A comparison of the current regulatory sys-tem with a proposed degree-of-hazard alter-native approach is illustrated in figure 1. Thecurrent system could lead to a situation of someover-regulation of low-hazard waste and someunder-regulation of highly hazardous waste,i.e., if the final management standards do not re-flect stringent controls. This could result in animbalance in the ratio of management costs andthe level of risk that results from the manage-ment choice. Instead of optimal managementcosts and potentially low levels of resulting risk,the consequences are uncertain (dotted lines)and could be either high management cost forlow-risk waste or low management costs withpotentially high levels of risk resulting from themanagement choice. Assuming that classifica-tion criteria can be developed that will correctlydistinguish degrees of hazard (such an assump-tion cannot yet be made with certainty), thealternative approach has the potential for reduc-ing uncertainty and providing a more appro-priate balance between management costs andthe expected level of risk resulting from the man-agement choice.

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III

Concept of Degree of Hazard

As part of the decision process of whether to incorporate a degree-of-hazard concept into Federal regulations, it is appropriate to examine thetechnical basis of the concept, its application in a classification system, ob-jectives and purpose, economic effectiveness, and uncertainties that sur-round implementing the concept for management purposes.

TECHNICAL BASIS

The degree to which accumulation and dis-persion of nonnuclear industrial hazardouswaste (NIHW) could pose a hazard to humanhealth and the environment depends on manyfactors as illustrated in figure 2: characteristicsof the waste contributing to its toxicity and theneed for safe handling (e. g., ignitability, cor-rosivity, and reactivity); concentration andduration of the exposure; properties that deter-mine its movement in the surrounding environ-ment, the potential for degradation and ac-cumulation in living organisms; the sensitivity ofexposed organisms to the waste; and site-specificenvironmental and management conditions thatenhance or inhibit movement of the waste to apoint for potential exposure. Because of thepotential for both acute and chronic toxicity,this factor has received the most attention whendeveloping degree-of-hazard criteria for clas-sification systems.

The toxicity of NIHW is a function of the in-herent capacity of waste constituents to produceadverse effects. The major determinants of the

magnitude of these effects are the characteristicsof waste (e. g., chemical, physical, and toxi-cological properties), the quantity of the wasteconstituent to which humans and other orga-nisms are exposed for a specific period (e. g., thedose, which equals the concentration availablefor some hours, months, or years), and the sen-sitivity of organisms being exposed (e. g., oxygenis highly toxic to anerobic bacteria but not tohumans, and herbicides directly kill plants butnot animals). Of these factors, toxicity and doseare of prime importance when assessing thepotential hazard of NIHW.

For any chemical there is a dose level that willproduce adverse effects in any organism; like-wise there is a concentration sufficiently lowthat no adverse effect can be observed (i. e., theresponse observed in the test population cannotbe distinguished from normal background inci-dences). Chemical and physical properties of theparticular chemical and the sensitivity of an af-fected organism are factors that influenceamounts required to cause harm. Thus, the dose

SOURCE: Office of Technology Assessment.

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of one chemical required to produce death in onespecies (e. g., rat) will be different from the lethaldose of another chemical for that same species;the lethal dose for one chemical also will varyamong species (e. g., monkey, dog, and human).In addition, not all animals or humans respondto the same concentration or exposure route in asimilar fashion. For example, nitrates in watercan be ingested by an adult human with no ad-verse effect, but these nitrates at certain concen-trations are toxic to infants. Finally, some com-pounds are toxic if inhaled, but do not present arisk if ingested or if applied to the skin (e.g. silicasand).

Differences in concentrations that can lead toa hazardous effect are particularly significantwhen considering constituents of NIHW. Ex-amples of these differences for acute toxicity arepresented in table 1. All of the compounds pre-sented in this table have been designated as haz-ardous constituents by EPA based on resultsfrom scientific studies of toxicity, carcinogen-icity, mutagenicity, or teratogenicity. (13) Theamount of each substance listed in the table thatis required to produce the same result (i. e., deathin 50 percent of the test population) varies great-ly and ranges from 3 mg/kg for cyanide to 5,000mg/kg for toluene. (14) (It is interesting to notethat the lethal dose for a commonly used prod-uct—table salt—is equal to 3,000 mg/kg, anamount less than that for toluene. Because of thelack of evidence that salt is carcinogenic,mutagenic, or teratogenic, it has not been des-ignated a hazardous constituent for waste. Astable 1 suggests, not all constituents of NIHWare equally toxic; the level of toxicity depends

Table 1 .—Toxic Doses for Selected HazardousWaste Constituents

Compound LD50a

Cyanide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Phenylmercuric acetate . . . . . . . . . . . . . . . . . . . . . . . 30Dieldrin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Pentachlorophenol . . . . . . . . . . . . . . . . . . . . . . . . . . . 50DDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113Naphthalene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,780Toluene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5,000aAmount (mg/kg body weight) that IS lethal for 50 percent of the test Popula-

tion, in these examples followlng oral administration to rats.

SOURCE: Examples of compounds are taken from EPA regulations, sec. 261.33and app. Vlll (13). LDM concentrations are taken from I?eg/stry o/TOXIC Effects of Ctrernmal Substances, 1980 edlfforr (14).

on properties of the waste constituents, amounts(dose) available for uptake by plants and ani-mals, and concentrations accumulating in sur-face and ground water.

The quality of an adverse effect (i.e., im-mediate death, reversible or irreversible illness)is also influenced by the exposure period. Alarge quantity of any compound given in a singledose can produce death in organisms (humansincluded). For some types of substances del-eterious consequences may not be observed ormay be much less serious when the same dose isencountered over a long time period. For exam-ple, although table salt can produce severe ef-fects at extremely high doses, small amounts in-gested during prolonged use do not often presenthealth problems, except for particularly sen-sitive individuals. The importance of concentra-tion and exposure period in determining poten-tial risk is the basis for setting standards thatdescribe permissible levels of some compoundspresent in our food, water, and air.

Chemical and physical properties of NIHWand interactions among constituents determinethe potential for degradation and accumulationin organisms, as well as their movement in theenvironment. Some classes of compounds can bedegraded easily by micro-organisms or throughphysical processes such as photolysis andhydrolysis. Other compounds are extremelystable and can accumulate to dangerously highlevels in the environment or organisms. Concen-trations and interactions of waste constituentsalso influence rates of degradation and ac-cumulation. Likewise, interactions among wasteconstituents can result in products withsolubilities different from the original com-pounds, thus affecting their movement amongenvironmental media.

The actual exposure of humans and otherbiota to waste constituents depends not only onchemical and physical properties of the wastebut also on characteristics of the storage, treat-ment, or disposal system. Rates of movement ofNIHW in the environment to points of potentialexposure are influenced by such factors as typeof soil, climatic conditions at the site, hydro-geological factors (e. g., the presence of under-lying bedrock or aquifers), and “steady-state”

10

conditions can be disrupted by natural disasters, ●

such as floods or earthquakes. Some chemicalsmay migrate rapidly through the environmentthat surrounds the management site and may ac-cumulate in surface or ground water; others maybind with soil particles and remain isolated from ●

vegetation or water. Thus an analysis of thepotential risk that NIHW will pose to human ●

health or the environment must include a con-sideration of not only the hazard potential of ●

constituents but also the fate of constituents ortheir degradation products should they move ●

from the disposal storage, or treatment site.

The degree to which the presence of a specificwaste produces a hazard requires assessment ofcertain critical information:

toxicological data including limits of confi-dence (hazards associated with exposures ofspecific organisms to specific chemicals atspecific concentrations for specific dura-tions);safety evaluations (hazards associated withignitability, corrosivity, and reactivity);waste loads (chemicals and quantities to bestored, treated, or disposed at a site);environmental fate (factors influencing themovement of waste at a site); andexposure (estimates of the chemical concen-tration and residence time at the point of ex-posure by organisms, e.g., in groundwater).

DEGREE= OF= HAZARD CONCEPT V. HAZARD CLASSIFICATION

Degree o f hazard i s a concept whichacknowledges that various waste managed ormismanaged in various ways at different sitespose different degrees of hazard to the public.The practical application of this concept, how-ever, requires some means of using data and in-formation to carry out a specific task, such aspermitting a facility for waste management. Inother words, there must be some measure of dif-ferent degrees of hazard if the concept is to beapplied.

A formal classification system of some typecould be used to apply the degree-of-hazard con-cept because the following two conditions aresatisfied:

particular waste, management strategies,and sites have important shared characteris-tics; andscientific criteria and data that describe haz-ards are either available or can be, in princi-ple, obtained to make classification an ob-jective and quantitative system.

An alternative is to apply the degree-of-haz-ard concept in a qualitative manner, i.e., sometype of “go/no-go” system in which waste, orcombinations of waste and management sys-tems, are labeled as hazardous or not hazardous,

or perhaps as low or high priority. Such quali-tative approaches, however, usually use a min-imal amount of technical data and scientific in-formation. There is little effort to apply estab-lished criteria either on a case-by-case basis or tobroader applications. Moreover, such qualita-tive approaches make it extremely difficult toanalyze resulting decisions.

The primary advantage of a classification ap-proach based on a degree-of-hazard concept isthat a systematic, technical framework for deal-ing with complex cases is provided. This ap-proach can be both reactive and anticipatory.Because a qualitative approach requires less ef-fort to develop criteria and data, its apparentsimplicity may be attractive from a program-matic perspective. However, it has little valuefor long-term organization of information andunderstanding of unifying principles. Moreover,information obtained in a qualitative approach,usually on a case-by-case basis,ate for quantitative analysis.

Objective and PurposeClassification System

The objective of classifyof hazard is twofold:

is not appropri-

aof

ng NIHW by degree

11

to identify waste that pose the most severethreats to human health and environmentaldeterioration, andto allow development of cost-effective man-agement strategies for each level of hazardwithin the classification scheme. (Althoughtransportation is an important aspect of amanagement strategy, the OTA assessmentof NIHW does not include transportation ofmaterials from generator to disposer. )

The basic premise of any system for categorizingNIHW, however, is that the waste and/or con-stituents of the waste stream can be grouped ac-cording to those properties that define quantifi-able effects and determine exposure under spe-cific conditions. Because waste streams often cancontain more than one hazardous constituent, itis unlikely whether enough information on thesetypes of properties is currently available for ac-tual waste streams. Information on individualconstituents (once identified within the wastestream) is relevant, and would permit a possibleminimal estimate of degree of hazard by com-piling the combined results, ignoring synergisticand antagonistic interactions among constitu-ents. As pointed out in a report by the Sur-geon General, the necessary information, how-ever, is not yet available for many of the wastec o n s t i t u e n t s .

A review . . . suggests that toxicologic infor-mation is deficient or missing. . . Many of thechemicals are not commercial products but aretheir precursors or process intermediates. A ma-jor toxicologic problem is that humans are likelyto be exposed to a combination of mixtures ofchemicals. There are virtually no data on or ex-perience in testing mixtures of chemicals for po-tential health effects.

Drawing upon specific technical information,a classification system could rank waste andwaste streams by degree of hazard. Differentcategories could be established according tospecified ranges of the probability of injury tohuman health or the environment that mightresult if the waste or waste constituents were toescape from the management site. In addition,management options could be matched to eachclass of waste to assure that NIHW are handledin the most cost-effective manner possible. This

match may not always be easy to accomplish.Conceivably some waste could be difficult tomanage effectively, regardless of the identifiedlevel of hazard, An example is the PCB-con-taminated sediment proposed for dredging fromthe Hudson River, Because of the relative con-centrations of PCBs within the volume of sedi-ment removed, incineration is impractical andlandfilling is considered by many to be un-desirable.

The development of a classification system,however, has four requirements:

1.

2.

3.

4.

establishment of standard criteria andmethods, which are widely available andgenerally accepted by the scientific com-munity;identification of widely accepted indicatorsof the relationships of real-world exposureto potential toxicity;definition of acceptable levels of hazard foreach category in the classification system;andan equitable and inexpensive mechanism toadminister the program.

Fulfillment of these requirements will not be sim-ple, as there currently is debate about the besttesting scheme (#I); and choice of indicator spe-cies (#2); particularly when evaluating chemicaleffects on the environment. (16,17)

Classification of waste by degree of hazardcould serve several purposes:

●

●

●

●

●

it could facilitate establishing priorities ofNIHW for inclusion in Federal or State reg-ulations;it could indicate the level of emergencymeasures required in the event of an acci-dental or deliberate spill;it could set priorities in use of scarce high-security landfill facilities or more costlytechnologies for treatment or disposal;it could influence general management pol-icies that determine the stringency of regu-lation, liability coverage, or the requiredlevel of monitoring; andit could provide a scale by which cost fac-tors are included in determining the choiceof management procedures.

12

Economic Effectiveness

Compared to present Resource Conservationand Recovery Act (RCRA) regulations, the useof a hazard classification system could changedramatically the way in which many hazardouswaste are disposed. Many facilities treat allwaste similarly and costs to users are generallyhigh; with a hazard classification system it maybe possible to reduce costs for the disposal ofsome less hazardous waste. Because of the highhazard posed by some waste now being handledin a least costly (but legal) manner, the disposalmethod may have to be changed to a more ex-pensive practice. The basis for requiring such achange in disposal practices is that the morecostly management alternative would be moreeffective in detoxifying or destroying waste clas-sified as extremely hazardous.

In order to illustrate the potential economiceffectiveness and logic of applying a degree-of-hazard classification system, decision analysiscan be made by using proxy disposal alterna-tives, as illustrated in figure 3. This comparisonassumes that landfill disposal corresponds to cur-rent RCRA regulations without use of a degree-of-hazard classification. Using this type of classi-fication, extremely hazardous waste would beincinerated in this example to assure their com-plete destruction. Although landfills have a

Figure 3.— Decision Analysis Illustrating the Impactof Degree of Hazard on the Choice of Management

Practice

lower cost per ton of waste, there is some prob-ability of failure. Failure is defined as the crea-tion of a hazard for people or the environment atsome future time, even using currently acceptedbest available technology and engineering judg-ment. The costs used in this figure are based onpresent technology and practices; the cost ofcleanup represents an average number based ondocumented remedial activities. These figures,however, should not be considered precise, andare used only for illustration.

The purpose of using a decision analysis is toillustrate that although incineration may appear,in the short term, to be substantially more ex-pensive than landfills, when the probability offuture damage (the critical probability in this ex-ample is 15 percent) and cleanup costs ($2,000/ton) are relatively high, the decision to chooseincineration is logical and economical. For thisillustration, it is assumed that cleanup costs areborne (directly or indirectly, such as throughinsurance costs) by the decisionmaker, who isconsidering alternatives. In other words, when awaste is considered to present a high enoughhazard and major risks are taken into account(internalized into the economic decisionmak-ing), using a management strategy with higherinitial costs than other alternatives can be appro-priate. If the perceived or estimated probabilityof landfill failure is 20 percent (as in example B infig. 2), then incineration costs are $100 less perton than landfill costs. When the probability isreduced to 10 percent (e. g., a value associatedwith a lower degree of hazard for a differentwaste or a different site), however, landfillbecomes the most cost-effective alternative,assuming that monitoring is 100-percent effec-tive and cleanup takes place before damage oc-curs to human health or the environment.

SOURCE Off Ice of Technology Assessment

13

UNCERTAINTIES IN IMPLEMENTATION

No matter which degree-of-hazard classifica-tion system is considered for use with NIHWmanagement, uncertainties regarding potentialhazards will always exist due to limited data onwaste, health and environmental effects, andsites. If the uncertainties are identified andacknowledged, a workable system might still bedeveloped. The major requirement in formu-lating a classification system is the assurancethat both objectives of a degree-of-hazard ap-proach are met, It is not sufficient to only iden-tify those NIHW of priority concern; if a degree-of-hazard system is to be effective, managementstrategies that reflect differences among categor-ies of hazard also are needed. Design of treat-ment and disposal facilities needs to focus on thecapability to minimize off site migration of wasteconstituents; while this focus is necessary, itcould make permitting a more difficult task asprediction of offsite migration is often difficult.The impact of this type of system on large andsmall industries is also unknown.

Implementing the mandate of RCRA througha regulatory approach based on degree of hazardrequires development of a realistic, yet uncom-plicated, system. This point was emphasized in arecent report by the Conservation Foundationon developing a classification system for man-agement of low-level radioactive waste.

A workable and enforceable system must bedevised that takes account of limited financial,institutional, and physical resources. When ill-conceived rules exist, the public and participantsin the waste management system will disobeynot only the senseless rules but also the signifi-cant, well-drafted ones. Compliance is especial-ly important with rules directed towards defin-ing and classifying wastes, since ignoring safe-guards at this initial step will hinder the effec-tiveness of subsequent stages of waste dis-posal.(18)

Degree of Hazard in the CurrentRegulatory Approach

Those regulations aimed at defining whichwaste are hazardous are not currently based on astrictly interpreted degree-of-hazard concept:the established criteria identify waste only ashazardous or nonhazardous. If a waste stream isto be considered hazardous and therefore withinthe jurisdiction of the Resource Conservationand Recovery Act (RCRA) regulations, it mustfirst meet one of three criteria, and then it isevaluated by the Environmental ProtectionAgency (EPA) to determine whether listing is re-quired. EPA has chosen in some instances touse considerable discretion in applying the sec-ond and third criteria when designating a wastestream as hazardous, and in others to apply ap-pendix VIII of EPA’s regulation in an indiscrimi-nate manner. The three criteria are:

● The waste exhibits any of the characteristics(i.e., toxic, ignitable, corrosive, or reactive)identified in subpart C, Characteristics ofHazardous Waste, of the regulations. (It isthe responsibility of industry to determine ifa waste meets this criterion. )

● The waste is fatal to humans in low doses;or studies indicate the following acute tox-icit y levels: oral LD50 in rats—less than 5 0mg/kg, inhalation LC50 in rodents—lessthan 2 mg/l, dermal LD50 in rabbits—lessthan 200 mg/kg; or “. . . is otherwise capa-ble of causing or significantly contributingto an increase in serious irreversible, or in-capacitating reversible, illnesses.’’

The waste contains any constituents listedin appendix VIII, Hazardous Constituents,of the regulations, unless after evaluatingseveral factors, “. . . the Administratorconcludes that the waste is not capable ofposing a substantial present or potentialhazard to human health or the environmentwhen improperly treated, stored, trans-ported, disposed of, or otherwise man-aged. . .“ (13)

Based on these criteria, EPA has prepared listsof designated hazardous waste from nonspecific

14

sources, specific sources, and discarded productslisted as acute hazard or toxic waste. EPA can,and probably will, make additions to these fourlists as well as to appendix VIII and could de-velop other lists of waste classes that it considersto be hazardous and therefore subject to reg-ulation.

Development of a regulatory framework formanaging NIHW has just begun; thus an evalua-tion of the effectiveness of current regulatory ap-proach is premature. Although a degree-of-haz-ard scheme based on specific criteria has notbeen explicitly applied by EPA, incorporation ofthe concept that different hazards exist is impliedor used in some sections of EPA proposed regu-lations, With reference to the degree-of-hazardconcept, and the use of phrases such as “sub-stantial threat, ” “hazard posed, ” and “extentnecessary to protect human health and environ-merit, ” an opportunity is provided for judg-ments to be made, probably in the courts, with-out technical basis. To date, no scientificallybased criteria have been established by EPA thatcan be used to make decisions about threats orhazards posed or the extent to which humansand the environment are protected. Put anotherway, many generators and disposers of waste aswell as third parties such as insurance companiesface an “unbounded” situation (e.g, in settingliability limits), with no programs being devel-oped for adding substantive meaning to thequalitative language frequently used in proposedregulations.

Table 2 illustrates selected sections of the pro-posed regulations where degree of hazard maybe considered by the permitting authority, eitherin identifying NIHW or in the management ofNIHW storage, treatment, or disposal. For ex-ample, EPA has excluded from federally per-mitted disposal sites those waste in amountsthat are less than 1,000 kg/month (for ad-ministrative convenience) and is considering afurther change to reflect tighter restrictions (lessthan 100 kg/month) suggesting that these are

15

Table 2.—Selected Examples of a Degree-of-Hazard Interpretation in Current RCRA Regulations

Identification of NIHWSmall quantity generators.—Waste from a small quanti-

ty generator are not subject to regulation under parts262-267 and 122-124 and are not subject to the notifica-tion requirements of 3010 of RCRA. A small quantitygenerator is one who generates less than 1,000 kg ofwaste per month, or less than 1 kg of acutely haz-ardous waste.

Criteria for listing hazardous waste.—One condition forlisting a solid waste as a hazardous waste is if thewaste contain any of the constituents listed in app. VIllunless after considering any of the factors listed (e.g.,nature of toxicity, persistence, bioaccumulation poten-tial and migration potential of the constituents, andquantities of waste generated) the Administrator con-cludes that the waste is not capable of posing asubstantial threat to human health or the environment.

TransportationPretransport requirements. -Packaging required in

accordance with DOT regulations, which are based onhazard classes.

Labeling required in accordance with DOT regulations,which are based on hazard class.

Marking required in accordance with DOT regulations,which are based on hazard class.

Placarding required in accordance with DOT regula-tions, which are based on hazard class.

Spills. —Use DOT spill-reporting system, which is basedon severity of spill.

EmergencyPreparedness and prevention.—

●

●

●

Facility design and operation.—Design, construct,maintain, and operate facility to minimize fire, explo-sion, or release of hazardous waste, which wouldthreaten human health and the environment; includesuse of performance standards.

Emergency equipment.— Emergency equipment re-quired only if the waste handled pose a hazard, whichrequires specific kinds of equipment.

Arrangements with authorities.—Arrangements re-quired as appropriate for the type of waste handledand the potential need for such services.

Contingency plan and emergency procedures.—Planmust be designed to minimize hazards to human healthand the environment from fires, explosions, or releaseof waste.

FacilitiesSecurity.— Prevent unknowing entry and minimize possi-

bility of unauthorized entry, unless contact with the

waste will not injure unauthorized persons or livestockand if unauthorized entry will not result in inability tocomply with standards.

Environmental performance standard for new landdisposal facilities.—Prevent ion of adverse affects to

ground water, surface water, air quality, and subsur-face environment through consideration of parametersincluding the volume, physical and chemical character-istics of the waste in the facility, the potential forhuman health risks caused by exposure to waste con-stituents, the potential damage to wildlife, cropsvegetation, and physical structures caused by exposureto waste constituents, and the persistence and per-manence of the potential adverse effects.

Regional Administrator may waive any of the design,operation, closure and postclosure requirements toachieve treatment of a waste provided the environmen-tal performance standard is met.

Regional Administrator may specify additional re-quirements where necessary to comply with the en-vironmental performance standard.

Closure: plan and fund.—Closure must result in control,minimization, or elimination of postclosure releases tothe extent necessary to protect human health and theenvironment. Fund required to meet cost of closure.

Insurance: sudden and nonsudden.—Minimum liabilityamounts specified may be increased or decreaseddepending on hazards posed. Premiums charged reflectdegree and duration of risk.

TechnologyUnderground injection.—An injection well must be de-

signed to assure compliance with the environmentalperformance standard.

An injection well must be operated in a manner thatwill comply with the environmental performance stan-dard.

Methods for operating an injection well must reflect aconsideration of the volume and physical and chemicalcharacteristics of the waste injected in the well.

Incineration.—Regional Administrator selects principleorganic hydrocarbons (POHCs) based on hazard posedconsidering incinerability, concentration and quantity.

Performance standard requiring 99.99 percent destruc-tion of selected POHCs.

Range of acceptable operating limits determined foreach waste feed.

SOURCE Consideration of Hazard In the Regulations unpublished document from Environmental Protection Agency, Off Ice of Solid Waste

not sufficient quantities to pose a threat to humans or other organisms. ) The pretransporthealth or the environment. (These exclusion requirements are based on regulations of the De-amounts do not consider the potential toxicity of partment of Transportation that, in turn, arethese waste, however; a very toxic waste pro- based on classes of hazard. The regulations gov-duced in small quantities could be hazardous to erning spills are based on the ‘severity’ of the

16

spill. (No definition of severity is provided andthe March 1981 craft of the National Contin-gency Plan defines quality of a spill according tothe size of the discharge.) The proposed facilitystandards are based on performance rather thanspecific design, but do not provide criteria forassessing performance; if the type of waste orthe environmental conditions surrounding thesite are such that little or no migration of constit-uents were possible from the site to potentialsources for exposure of humans or other livingorganisms, application of performance stand-ards could permit less stringent control measuresto be used. (20)

As the regulations are currently designed thestringency of control for any facility whetheronsite or off site is apparently determined by thepermitting authority within each State or region.While this may provide the opportunity to reg-ulate NIHW disposal by degree of hazard, uni-form application of this type of approach is notassured, particularly in the absence of specifiedcriteria for evaluating predicted performance offacilities. EPA’s approach does permit site- andwaste-specific flexibility in permitting facilities.Left to the interpretation of individual permit-ting authorities, confusion and unequal enforce-ment could result. Some of the confusion and in-

consistency might be avoided through publicparticipation (i. e., through concern about sitingnew facilities) in the permitting process andthrough the use of litigation to prevent author-ization of those facilities that are perceived asnot being safe. It is uncertain, however, if theseare the most appropriate ways to achieve effec-tive management and enforcement of EPAregulations.

Because RCRA regulations are in the interimfinal stage, it is possible to apply the concept ofdegree of hazard within the current structure.For example, specific criteria based on degree ofhazard for the waste to be handled could be de-veloped for assessing the performance of stor-age, treatment, or disposal facilities. In addition,a degree-of-hazard classification and manage-ment system could be incorporated into the reg-ulations incrementally, thus reducing transi-tional uncertainties that would arise if the entireprogram were changed radically and suddenlyfrom its present design. As table 2 suggests, EPAis moving toward application of a degree-of-haz-ard concept in a qualitative manner. The majoruncertainty is whether a rigorous classificationscheme with scientific criteria can be and shouldbe implemented fully within the regulations.

Methods for Classifying Waste andFacilities by Degree of Hazard

There are several ways to develop a system ofclassifying both NIHW and management facil-ities by degree of hazard: grouping by technicalcriteria, rank order by test results for specificcharacteristics, the use of multiple discrim-inatory factors for categorization that con-centrates on important exposure and effectsdata, or classifying by environmental contain-ment, Of these various methods, only the firsthas received much attention. The other schemeshave been applied in narrowly focused tasks and

are very speculative options for adaption inmanagement of nonnuclear industrial hazardouswaste (NIHW). The systems presented in the fol-lowing discussion serve only as examples ofthese various types of classification method-ology. The omission of any specific design doesnot reflect a judgment as to the appropriatenessof the omitted example. Because of the variety ofpotential designs, the intent is to indicate thediversity of methods, rather than to discuss allpotential approaches.

CLASSIFICATION USING TECHNICAL CRITERIAAs States begin formulating their own regu-

lations for management of NIHW, the majorityare using a scheme based on technical criteria toidentify waste as hazardous. At present, how-ever, definitions of the term hazardous varywidely among the States. For example, a recentsurvey indicated that 45 States use general orqualitative definitions of hazardous, but theterm is not uniformly applied in all Statelaws. (21) Among these 45, 34 States includecharacteristics such as flammability, cor-rosiveness, and toxicity to narrow their defini-tion of hazardous waste, but only eight of theseStates specify test protocols and acceptableranges for test results. Thirteen States followedthe lead of the Environmental Protection Agen-cy (EPA) and developed lists of NIHW. Of thetotal 45 States in this survey, only five con-sidered measures of volume or specific chemical,physical, and toxicological characteristics todistinguish between more than one class ofNIHW; these include California, I l l inois,Maryland, Pennsylvania, and Washington. FourStates—California, Rhode Island, Texas, andWashington—proposed detailed programs usingdifferent technical criteria of toxicity to classifyNIHW in response to the 1978 proposed regula-tions. Recently other States, including Ken-tucky, Ohio, and Michigan, have developed

some form of a degree-of-hazard program formanaging NIHW. The programs discussed be-low are presented only as illustrations of thistype of classification methodology.

California.—California has a two-tier systemfor classifying hazardous waste, hazardous andextremely hazardous. Criteria based on toxicity,flammability, pressure-generating reactivity,corrosivity, irritancy, and sensitizing propertiesare used to describe each category, The majordetermining factor that distinguishes betweenthe two groups seems to be the level of toxicity.To designate a waste as hazardous, certain tox-icity measurements are required: acute toxicity(i.e., short-term response), carcinogenicity,chronic toxicity, and estimates of degradabilityand bioaccumulation (see table 3). The categorydesignated as hazardous has acute toxicity testresults in a range of 51 to 2,000 mg/kg, containssubstances that are known or suspected to becarcinogens, are considered nondegradable, ac-cumulate in tissue, and can contribute to chronichealth problems. The extremely hazardous cat-egory includes those materials that are shown tohave high levels of acute toxicity (equal to or lessthan sO mg/kg), that are defined by Californialaw as carcinogens, or that have been tested inthe laboratory and results indicate that they are

17

18

‘Table 3.—Toxicity Criteria in the California System of Degree-of-HazardClassification

Limitsa

Extremely hazardous Hazardous

%tg of material/kg body weight of Organism

SOURCE. Sterllng Hobe Corp. (12).

potential carcinogens, cause chronic toxicity,are nondegradable, and accumulate in tissue.Except for differences between the moderate andhigh levels of acute toxicity and the State defini-tion of some carcinogens, no quantifiable meas-ures have been provided to distinguish the othertoxicity criteria between categories, except forthreshold limits of certain compounds that havebeen specified in the California legislation. Lim-ited technical justifications for minimal dif-ferences between criteria for classifying waste ashazardous or extremely hazardous have beenprovided,

Although the California proposal placesNIHW in different classifications, managementpractices do not vary between the two catego-ries. The waste ( i.e., hazardous or extremelyhazardous) are sent to the same type of facilityand treated in a similar manner. Transportationand admninistrative procedures for handlingNIHW (e.g., recordkeeping) are maintained sep-arately for each category. The utility of the pro-posed classification without differences in man-agement practices is dubious.

A further classification system exists in thisState under the authority of the Water QualityControl Board and is independent of the abovesystem. Waste are put into one of three groupsbased on the probability of ground water con-tamination. These waste are directed to match

facility sites that have specific geological struc-tural standards related to each group of waste.

Rhode Island. —The State of Rhode Island hasdeveloped and implemented a system that at-tempts to rank the materials using several char-acteristics of hazard, e.g., levels of toxicity, re-activity, flammability, and irritancy. Distinc-tions such as high, moderate, and slight are des-ignated for each characteristic. Qualitative andquantitative definitions of each level (e.g., mod-erate flammability) are provided. Responsibilityfor determining correct classifications of thewaste lies with the generator. The transportmanifest includes a description of waste constit-uents and the designated classification. Stateofficials use this information to verify that anappropriate classification has been made. If adisagreement about the assigned class resultsbetween generator and State officials, conflictsare resolved through further testing.

Industry representatives have worked closelywith State officials in formulating criteria foreach degree-of-hazard category. Althoughthis scheme is comprehensive and detailed, it iscurrently being used only in recordkeeping andfor limiting routes of transportation. The Statehas developed criteria for land disposal; how-ever, all waste are currently sent to out-of-Statedisposal faci l i t ies.

Texas.–Prior to development of the EPAproposed regulations, the Texas Department ofWater Resources proposed using a classificationsystem based on differences in the potential foradverse effects on human health or the environ-ment.(23) The definitions and specific measure-ments were derived to identify potential impactsresulting only through land disposal of industrialsolid waste. The system included both a list ofhazardous substances and criteria for desig-nating new waste as hazardous. Table 4 illus-trates the type of measures proposed for classi-fying materials. The basic difference betweenClass II and Class III in this scheme was that thelatter represents inert materials, e.g., essentiallyinsoluble and not readily decomposable materi-als including rock, brick, glass, dirt, certainplastics, and rubber. Placement of a NIHWwithin a particular class was to be based on anal-ysis performed by the appropriate State agency.

Some important characteristics of potentiallyhazardous waste (e.g., chronic toxicity, geneticimpairment, and persistence) were not includedin the Texas system. Also, criteria were designedsolely for use in land disposal and little indica-tion of the applicability of the scheme for othermanagement practices was provided. The Texasdefinition of Class I materials corresponded toEPA’s current definition of hazardous waste, asboth of the other classes identify relatively non-hazardous materials. If the plan were to be im-plemented under EPA regulations, State officialswould manage waste from Classes II and III on a

Table 4.—Criteria for the Texas System ofDegree-of-Hazard Classification

Class I Class II Class Illa

Hazard indexb . . . . >50 >50LD 50 measures c . . .p Hd . . . . . . ... , . . . <2.5, > 12 2.5 –12 2.5 – 12Corrosion ratee . . . <0.25 in/yr >0.25 in/yr >0.25 in/yrFlash pointf . . . . . . >140° F >140° F

asee text for Composltlonal differences between Class II and class Illbf+epreserlts the potential hazard to the environment If lmPrOPf3rlY disposed

based on measures of toxlclty and solubillty of the substance.cMedlan lethal dose; dose required to kill ~ percent Of a POPU(atlOfl exposed fo

the chem!cal of concern.dMeasure of actdlty or alkallnlty; pH 7 indicates neutral solution; <PH 7 In.

dlcates acidic Solut!on, >pH 7 Indicates alkaline or basic solutlon.ecorroslon rate on steel (SAE IOZO) at a test temperature of 130“F as detef-

mlned by NACE.f Determined by a Pensky+fartens Closed Cup Tester using ASTM Std. D.93-73.

SOURCE Sterllng Hobe Corp. (12)

waste- and site-specific basis. Management prac-tices for waste classed as hazardous (Class I)would closely follow the regulations byEPA. (23) Therefore, as presently designed thisproposed system does not really provide adegree-of-hazard approach.

One major drawback to these three systems(i.e., California, Rhode Island, and Texas) isthat there is no consideration of actual or poten-tial concentrations at the source of exposure. Asdiscussed previously, it is the concentration atthe time of exposure that has the greatest in-fluence on the severity of any adverse effect.Any system that does not consider dose levelcannot be consistently effective in providing rel-evant protection either for human health or formaintaining a clean environment. Another im-portant problem with these systems is that cri-teria for listing new waste as hazardous are notcomprehensive enough to adequately “catch” allpotential NIHW. Primary measures of toxicity,either in the hazard index or LD50 criterion, de-pend only on acute toxicity. No consideration isgiven to waste that may result in chronic healthproblems or long-term, low-level deteriorationof the environment. Thus a number of chroni-cally hazardous waste could pass the tests pro-vided in these systems, but could still pose haz-ards to humans and other organisms.

Washington.—The Department of Ecologyfor the State of Washington has developed aclassification system that includes some consid-eration of concentration and potential expo-sure, This system has two classes designatedas extremely hazardous and dangerous. The dis-tinguishing criteria among the two classes in-clude characteristics of persistence, concentra-tions in the waste stream, potential to cause ge-netic effects, level of toxicity, and concentra-tions of specific classes of known toxic chemicals(e.g., polycyclic aromatics). Table 5 illustratesthese distinctions. Extremely hazardous wasteare further ranked into two categories: 1) hazardresulting from toxic effects on humans and wild-life; 2) hazard attributed to the persistence of thematerial. Specific criteria for extremely hazard-ous waste include complex combinations of dif-ferent measures of acute toxicity and percentvolume of specific waste constituents. An im-portant aspect of this system is that the method-

20

Table 5.—Criteria for the Washington System of Degree-of-Hazard Classification

Extremely hazardous Dangerous

Oral, rat, LD50

a. . . . . . . . . . . . . . . . . . . . . . <500 mg/kg <5,000 mg/kgAquatic fish, LC50 . . . . . . . . . . . . . . . . . . . <100 mg/l <1,000 mg/lHalogenated hydrocarbons . . . . . . . . . . >1% >0.01%Polycyclic aromatics . . . . . . . . . . . . . . . . >1% NoneConcentration of heavy metals in EPA

leach test. . . . . . . . . . . . . . . . . . . . . . . . 10,000 x DWSb 100 x DWSNonbioaccumulative carcinogens . . . . . — IARC C human or animal:

positive or suspectedCorrosivity, reactivity, ignitability . . . . . — EPA definition

aFor Purg compounds or Slrnple rni xtures book designation using the NIOSH Register and the designation diagram are POSSLble, set! appendix.

bDWS = drinking water standard.CIARC =, International Agency for Cancer Research. This group weighs published studies on suspected cancer causing

agents and issues findings.

SOURCE: Provided by E. W. Tower, Solid Waste Management Division, Off Ice of Land Programs, Department of Ecology,State of Washington, Olympia, Wash.

ology has been developed for classifying wastemixtures and permits an evaluation of potentialhazard at the point of exposure. (24) (see also ap-pendix.) Any nontoxic waste in amounts exceed-ing 100 lb/week that is considered corrosive, ex-plosive, or flammable is classified as dangerouswaste. Disposal of this class of materials is regu-lated less stringently than extremely hazardous,

In this system, the generator is responsible fordetermining the correct classification of a waste.If toxic constituents are known, classificationcan be made without testing; if waste compo-nents are not known with any degree of cer-tainty, either qualitatively or quantitatively,analytical tests must be conducted to identifyconstituents and determine their degree of haz-ard. The State has developed standardized ratand fish bioassays to be used as biological in-dicators of toxicity in the degree-of-hazard as-sessments. Tests must be performed to ascertainflammability and corrosivity of dangerouswaste. A prose test (narrative description) is ap-plied to determine explosive potential.

The degree-of-hazard approach has also beenapplied to facility standards. Washington Statelaw requires that extremely hazardous wastemust be disposed at the Hanford site where theclimate and topography of the eastern section ofthe State is best suited to contain these more haz-ardous wastes. Dangerous waste can be disposedof at any other permitted site, which follows thecriteria established by EPA. State officials con-sider that these restrictions address the exposurepotential of NIHW to humans or other biota.

The Washington State system has been inoperation since 1978 and as yet no major prob-lems have emerged. This approach for classi-fying and managing NIHW appears more strin-gent than the EPA regulations. Therefore, prob-lems could develop for interstate transportationand the acceptance of out-of-State waste byWashington State disposers.

Other Schemes.—In reponse to the December1978 publication of regulations proposed for im-plementing RCRA, 12 classification schemesusing a degree-of-hazard approach were pro-posed to EPA in addition to the Statesystems. Most of the 12 schemes formulatedtechnical criteria using qualitative or quan-titative measures of toxicity, safety hazards, en-vironmental fate, and management practices.Many of the proposals lacked detail on technicalcriteria and served only to suggest how a classi-fication system might be developed. Three ofthese proposals did provide some detail aboutthe type of criteria to be applied in each cat-egory. Table 6 illustrates these characteristics.

All of the proposed schemes, including thoseof the four States, have major disadvantages.Table 7 provides a comparison with respect tothe type of technical criteria required. Thosecharacteristics that may be considered to be ofprime importance for identifying NIHW includeestimates of potential genetic impairments (e. g.,carcinogenicity, mutagenicity, teratogenicity),measures of acute and chronic toxicity, degree ofpersistence and bioaccumulation, estimates ofpotential concentrations in waste, indications of

21

Table 6.— Proposed Technical Criteria for Classifying Nonnuclear Industrial Hazardous Wastes

System 1 System 2 System 3

Class I Genetic impairment and persistence;or high-level acute toxicity; ormoderate acute toxicity and persis-tent; exceeds 1,000 X drinking waterstandards.

Class II Genetic impairment and not persis-tent; or moderate acute toxicity andbioaccumulates or persistent; or 300to 1,000 X drinking water standards.

Class Ill Low acute toxicity and bioac-cumulates or persistent; or 100 to300 X drinking water standards.

High acute toxicity and concen-tration exceeding 100-mg/kgwaste; or reaction at normaltemperature and pressure; oror forbidden explosive (by law).

Flash point <1000F, consideredhazard during management; orflammable compressed gas; orpH <2 or >13; or corrodes steel;or highly reactive; or exceeds100 X drinking water standards.

Flash point 100° - 200° F; orhazard during burning; pH 3-12;or less than 100 X drinkingwater standards.

Moderate to high acute toxicity; orgenetic impairment, persistent orbioaccumulates; or reactive orinfectious.

Low acute toxicity; or ignitable,corrosive or reactive; or low in fee-tibility.

SOURCE Sterllng Hobe Corp (12)

22

the potential for exposure to sensitive biota or tohumans, and measures of ignitability, corrosiv-ity, and reactivity. Except for the WashingtonState system, concentrations of the waste-streamconstituents have not been considered. In mostof these systems, chronic toxicity is not a cri-terion, nor is there any assessment of the poten-tial for movement from the waste site. Some ofthe proposed systems rely on previously set

standards, when such standards (e. g., waterquality criteria standards) exist for only a fewcompounds. This approach could permit someextremely hazardous waste constituents to re-main unregulated. Finally, none of the systemsto date has management strategies or facility cri-teria that relate to the different identificationcategories in a relevant way.

RAN K= ORDER CLASSIFICATIONS

With passage of the Toxic Substances ControlAct (TSCA) the need for mechanisms by whichchemicals could be given priority for further tox-icity testing received much attention. Sev-eral models have been developed that combinetest scores for a variety of toxicity tests: LD50 orL C50 ranges, carcinogenicity potency, chronichealth effects, teratogenicity potential, etc. Inrank-order schemes the compound of concernreceives a “score” that is based on a particularcombination of results from several types oftests. Those results or tests considered to bemost important for the assessment (i. e., carcino-genicity) can be weighted to reflect this relativeimportance. Once the composite score is cal-culated, chemicals can be ranked by their scoresand priorities established for further action.

Although the rank-order type of approach hasnot been applied directly to industrial waste,there is some potential for its usefulness inNIHW management. For example, table 8 illus-trates a rank-ordered system developed by theSta te o f Mich igan . The S ta te uses th i smethod to identify compounds for its CriticalMaterials Register. A system such as that illus-trated in table 8 could be adapted and used as ameans to classify waste or waste constituents ac-cording to degree of hazard. Particular testresults could have a greater influence on a haz-ard designation and thus receive more weight ina classification scheme. For example, scores forproperties such as persistence or bioaccumula-tion could be multiplied by a factor of two, giv-ing these characteristics greater weight in theranking. Hazard categories then could be des-

ignated by the total expected scores, forexample:

Combined scoreE x t r e m e l y h a z a r d o u s 46Moderately hazardous. ., 25-45S l i g h t l y h a z a r d o u s , 24

This range of categories is given only as anexample of how the system might operate.Before limits for each group could be definedand justified, careful consideration of all criteriais needed. Development of such criteria wouldrequire extensive research efforts.

Several schemes similar to rank-order assess-ments have been proposed as methodology forperforming hazard assessment, (28,29) Table 9 il-lustrates the types of factors included in assess-ments of potential biological impact and disper-sion of NIHW. Recently, ranked classificationsbased on the statistical technique of discriminantanalysis were proposed. This type of analy-sis was used to classify waste streams fromselected smelting and refining industries. Thisparticular approach was suggested as being ap-propriate for rank-order classification of man-agement practices or facility sites.

Recently this type of classification has re-ceived some criticism. (31) These criticisms focuson the following points:

combining scores of different effects intoone index for ranking purposes entails mak-ing a value judgment; and

● there is no logical basis for assigningweights to specific factors due to the diver-

23

Table 8.— Michigan’s System for Rank-Order Assessment of Critical Materials

1. Acute tox ic i ty

Score Category

Oral L D50 Dermal LD50 Aquatic 96 hour LC5 0

mg/kg mg/kg mg/l

7 <5 <5 <13 5-50 5-200 1-102 >50-500 >200-500 >10-1001 >500-5000 >500-5000 >100-10000 >5000 >5000 >1000● Insuf f ic ient in format ion

Il. Carc inogenic i ty

S c o r e Category7 Human pos i t ive ; human suspect ;

animal posi t ive3 Animal suspect2 Carcinogenic by a route other than oral or dermal;

strong potential carcinogen by acceptedmutagenicity screening tests or accepted celltransformation studies

1 Potential carcinogen by accepted mutagenicityscreening tests or accepted cell transformationstudies

o Not carcinogenic● Insufficient information

Ill, Hereditary mutagenicity

Score Category7 Confirmed4 Suspect - multicellular organisms2 Suspect - micro-organismso Not a hereditary mutagen● Insufficient Information

IV. Teratogenicity

Score Category7 Confirmed3 Suspecto Not teratogenic. Insufficient information

— ——. .SOURCE Michigan Department of Natural Resources (27)

Table 9.—Suggested Effect and Exposure Factors

Exposure Effects

Bioaccumulation Genetic impairmentPersistence Reproductive changesMobility Acute toxicityEnvironmental concentrations Chronic toxicityGeographic dispersion Ecosystem changesPopulation factors Dose factors

SOURCE Modified from TSCA-interagency Testing Committee, subgroup S(31)

v. Persistence

Score Category4 Very persistent3 Persistent2 Slowly degradable1 Moderately degradableo Readily degradable. Insufficient Information

VI. Bioaccumulat ion

Score Bioaccumulation Log P7 >4000 >6.003 1000-3999 5.00-5.992 700-999 4.50-4.991 300-699 4.00-4.499 <300 <4.00● Insuf f ic ient in format ion

VII, EstheticsScore Category

Fish tainting/taste andodor (threshold level

in water - mg/l)3 0.0001-0.0012 >0.001-0.011 >O.O1 -0.10 >0.1

VIII. Chronic adverse effects

S c o r e C a t e g o r y

4 Irreversible effects

2 Reversible effects

Foaming, f loat ingfilm, and/or major

color change

YesNo

1 Adverse effects by route other than oral, dermal oraquatic

o No detectable adverse effects● Insufficient information

sity and composition of the various testparameters.

It has been argued that this method of settingpriorities eliminates the necessary indications ofthe relative importance of any individual factor.For example, the fact that a chemical may bepersistent and produce chronic effects could bevery important, but might be overshadowed if

24

no other adverse effects were measured. Much the wide range of waste-management problemsdevelopmental work will be required before that currently exist.such rank-order approaches can be applied to

MULTIPLE DISCRIMINATORS

A new concept based on multiple discrimi-natory factors, commonly termed red-flag, isbeing considered as an appropriate way to rankchemicals under TSCA jurisdiction. In thisapproach a chemical receives scores based onspecific test results, similar to those presented intable 8. Within each test category, however, aminimum score termed a discriminatory factor(e.g., a score greater than 2 for persistence orgreater than 3 for bioaccumulation) is identifiedthat serves to “flag” the chemical for furtherattention.

A classification system for NIHW could bedeveloped using the red-flag approach and com-bining exposure and effect factors (see table 9).The discriminatory factors could be combined ina logical manner within each class. For example,a chemical might be classed as extremely hazard-

ous if it received high scoresflags) in areas of carcinogenic

(and therefore redeffects, chronic ef-

fects, bioaccumulation, persistence, and mobil-ity. Another example includes classificationsbased on a hazard index that is developed bycombining certain discriminatory factors; for ex-ample, by combining quantity discharge, bioac-cumulation, and persistence into one index valueor by using a combination of environmentalconcentration, bioaccumulation, and persist-ence. This type of analysis represents a new ap-proach in identifying priority compounds andcan be considered only as a speculative optionfor use in classifying NIHW. Before acceptanceor rejection of the concept, however, carefulstudy is needed to determine if this approach isappropriate for identifying as well as managingthe treatment and disposal of NIHW.

CLASSIFICATION BY ENVIRONMENTAL CONTAINMENT

Another speculative type of classificationsystem categorizes facilities by the ability tominimize escape of potentially harmful sub-stances. Here the emphasis is on managementrather than identification. Classification schemesfor sites are available, but these have focusedprimarily on identifying the hazard potential ofabandoned dumps .(33,34) With some modifica-tion these schemes could be applied to landfill,incineration, or treatment facilities as well.Although there are serious technical concernsover the rating levels presented in table 10, thissystem illustrates the types of variables that ap-pear to be appropriate. These include the dis-tance to nearest population and drinking wells,critical environments, distance to nearest surfacewater, depth from facility to ground water,amount of precipitation, soil permeability,bedrock permeability, and depth to bedrock.

Once facilities are classified, the waste streamscould be grouped according to those chemicaland physical properties that are major factorscontributing to the potential movement ofNIHW constituents from the facility to the sur-rounding environment. Appropriate classes ofwaste could be matched to management at theappropriate site. Such a classification has beensuggested previously .(35) For example, NIHWwith a high potential to escape from the facility(i.e., readily soluble in water) and not easily en-vironmentally degraded might be put into thosesites that could minimize exposure to humansand other biota. A system very similar to thisconcept has been considered for defining andclassifying low-level radioactive waste. (18) Ithas been suggested that management facilitiesfor low-level waste could be designed andclassed according to a specific containment time;

25

Table IO.—Suggested Environmental Parameters for Classifying Facility Sites

Rating factors

Population within 1,000 ft

Distance to nearestdrinking-water well

Distance to nearestoff site building

Land use/zoning

Critical environments

Distance to nearestsurface water

Depth to ground water

Net precipitation

Soil permeability

Bedrock permeability

Depth to bedrock

Rating scale levels

o0Greater than3 miles

Greater than2 miles

Completely remote(zoning notapplicable)

Not a criticalenvironment

Greater than5 miles

Greater than 100 ft

Less than 10 inches

Greater than 50percent clay

Impermeable

Greater than 60 feet

1 2 3

1 to 25

1 to 3 miles

1 to 2 miles

Agricultural

Pristine naturalareas

1 to 5 miles

51 to 100 ft

– 10 to + 5 inches

30 to 50 percent clay

Relatively impermeable

31 to 60 ft

26 to 100

3,001 ft to1 mile

1,001 ft to1 mile

Commercial orindustrial

Wetlands, flood-plains, and preservedareas

1,001 ft to1 mile

21 to 50 ft

+ 5 to + 20 inches

15 to 30 percent clay

Relatively permeable

11 to 30 ft

Greater than 100

0 to 3,000 ft

o to 1,000 ft

Residential

Major habitat ofendangered orthreatened species

0 to 1,000 ft

o to 20 ft

Greater than +20inches

O to 15 percent clay

Very permeable

o to 10 ftSOURCE: Modified from JRB Associates (33)

this containment potential is related to the half-life of radioactive waste. The report stresses,however, that “no one factor would control theassessment of risks, and . . . other screens mustbe considered. Screens for classifying waste. . . should include: toxicity, concentration,chemical and physical form, compounds thatwaste may decay to or become during storage,volume, and possibility of release and mobility. ”The report continues . . , “Since all waste do notrequire the same degree of containment or care,various types of disposal techniques should beused; this would more efficiently allocate limitedresources. It should be possible to save spaceand money while preserving or enhancing ad-ministrative simplicity. ” Although these state-ments were made for management of radioactivewaste, they are applicable to management of in-dustrial hazardous waste as well.

Table 11 illustrates a potential scheme forclassifying facilities based on the need to min-imize escape of hazardous components. Mate-rials could be classed according to the environ-mental mobility and degradable characteristicsand assigned for treatment or disposal in the ap-

propriate facility class. In such a system a facil-ity would not be limited to handling wastewithin its permit class but could receive wastewithin lower classifications (e. g., a Class Afacility could receive all classes of waste; Class Bfacility could receive Class B, C, and D wastebut not Class A). Although the prohibition oflandfills in the Class A designation may appearto be a radical action, restricted use of landfillsfor certain high-priority hazardous waste hadbeen considered by the New York State leg-islature. (36)

The California Office of Appropriate Tech-nology (OAT) has completed a comprehen-sive study of hazardous waste disposal inCalifornia. (37) Using currently available data,OAT identified six classes of high priority wasteand concluded that these waste were unsuitedfor land disposal. The study reviewed alter-native management options for these classes ofwaste and made the following recommendationfor use of the most secure landfills (Class I):

The State should abandon the concept ofClass I landfills as repositories for almost alltypes of hazardous waste by restricting land dis-

26

Table 11 .—Potential Classification Scheme Based on Containment and Destruction

Landfills Incineration or treatment facilities

Class A— Permitting requires specific opera-

tional criteria, detailed environmentalevaluation, and stringent monitoring;facility used for waste requiringspecial handling.

Class B— Permit corresponds to currently

proposed facility standards.

Class C— Permit by rule for recycling or routine

treatment or detoxification process.

Class D— Permitted to dispose of nonhazardous

waste.

Restricted unless specialauthorization provided byEPA.

Permitted, if in compliancewith technical standardsbased on ability to containNIHW.

Permitted for large volumespecialty waste (e.g., utilitywaste, oil-drilling waste).

Sanitary landfills.

Designed to destroy (incinerate or biodegrade)or detoxify (biologically or chemically)NIHW that pose extreme hazard to humanhealth or the environment; some potentialfor generating toxic residues.

Designed to detoxify (naturally or induced)NIHW within finite containment period andin compliance with technical standards.

Designed to handle readily degradable, ortotally recycled NIHW, or waste thatare incinerated without producing toxicbyproducts.

Municipal waste treatment and disposal.

SOURCE: Based on material provided by B. L, Simonsen, IT Corp., Wilmington, Calif.

posal to those waste which have been specif-ically identified as safe for this method ofdisposal.

It appears likely that this recommendation willbe accepted by the State legislature.

The basis for this is type of scheme is the abilityof a facility to properly contain the NIHW for aspecified time period and to match this timeperiod with the duration for degradation ormobility potential of the waste. Thus, thosefacilities that are shown to be able to contain thewaste for a specified time or are capable of com-pletely destroying the waste (e.g., incineration)could be used to handle NIHW that are shownto be highly persistent and nondegradable. If it isknown that controlled release is likely or that

there is potential for surface or ground watercontamination at some time in the future thenthese sites could be used to handle waste withdegradation potentials that match the expectedtime of escape from the facility. As mentionedabove, this is a highly speculative approach.Before implementation at any level of operation(i.e., National or State) is possible, full in-vestigation is needed to determine the properfacility-environment parameters, including facil-ities other than landfills, and to decide whethersuitable parameters can be measured for NIHW.A thorough review of the application of thisscheme to disposal of radioactive wastes couldprovide some insight into which factors are mostimportant.

Unresolved Questions

Because of the current lack of information anddata, none of the schemes discussed in the pre-vious section could be immediately implementedin a regulatory policy. Each approach has ad-vantages and disadvantages that require sub-stantial further evaluation. The systems thatpropose to classify on the basis of specific tech-nical criteria do not consider all of the character-istics that are important for hazard assessments.The more complete systems, California, Wash-ington, and System #1 (see table 7) do includethe majority of hazard characteristics: potentialto cause genetic impairment, acute toxicity,chronic toxicity, persistence, concentration (to alimited degree), bioaccumulation, and charac-teristics of safety evaluation. These approaches,however, do not consider directly such factorsas dose, exposure potential, environmentalmobility, and sensitive environments or popula-tions. (The Washington system addresses thesepoints indirectly. ) Approaches using rank orderor multiple discriminators (e. g., the Michigansystem illustrated in table 8) generally relyprimarily on effects data without much attentionbeing given as yet to exposure data. The multi-ple discriminator system, proposed for settingpriority chemicals under the Toxic SubstancesControl Act (TSCA), does include some envi-ronmental or exposure parameters and thuscould have greater promise for application inmanaging nonnuclear industrial hazardouswaste (NIHW). The advantage of classifyingfacility and waste according to containment ordestruction ability is apparent, but there isuncertainty with this approach also. Verificationis needed to assure that waste can be character-ized in a way that reliably quantifies the poten-tial for degradation and environmental mobil-ity. If it could be assumed that those persistentand relatively immobile chemicals are also thosewith the highest level of hazard, then the lack oftoxicity criteria in the last approach would notbe disadvantageous; however, conclusive evi-dence that supports this assumption is not yetavailable.

Although no perfect system exists at the pres-ent time, further consideration of the appro-

priate use of a degree-of-hazard concept in reg-ulating NIHW is warranted, given the increasedattention this concept has received domesticallyand internationally. A recent report of the NorthAtlantic Treaty Organization (NATO) indicatesthat definition and classification of hazardouswaste is a task that requires attention by mem-ber countries. The NATO countries havefollowed three approaches:

●

●

●

The

describing hazardous waste in qualitativeterms,defining hazardous waste using criteriabased on standard testing procedures, anddefining hazardous waste by the quantity ofharmful constituents.

end-result for each country has been an in-dustrial waste list that varies in detail and in thenumber of hazardous categories.

Before applying a full-scale effort towarddesigning an appropriate classification system,important questions require resolution:

● Is there is a need to change or modify thecurrent regulatory approach?

Can appropriate criteria for a degree-of-hazard classification be established?

. Can the analytical burden imposed on in-dustry be efficiently reduced by a degree-of-hazard classification system?

1. Is there a need to change the current Federalapproach?

Now that the Environmental ProtectionAgency (EPA) has begun formulating theregulatory structure for managing NIHW, anevaluation of the advantages and disadvantagesof a degree-of-hazard concept is appropriatebefore decisions can be made to implement thistype of approach. Consideration of what can begained by changing or modifying the currentstructure is needed. Serious questions concern-ing the degree-of-hazard approach include:

● What are the costs required of EPA foradditional research and development effortsaimed toward the design of an appropriatescheme? What are the costs in time lost for

27

28

●

●

●

●

regulating and enforcing proper manage-ment of NIHW while a scheme is being de-veloped? Any benefits derived from using aclassifying system based on degree of haz-ard must be greater or at least equal to thesedevelopment and opportunity costs.What evidence exists to support the conten-tion that use of a degree-of-hazard conceptin managing NIHW would be more cost ef-fective than the current program? To datequantitative evidence does not exist. An in-depth analysis of this point is needed beforeencouragement or condemnation of theconcept can be made.Is it necessary to change the current reg-ulatory structure in a drastic way? It maynot be necessary to apply a degree-of-haz-ard system as a replacement for the currentregulatory approach. The EPA program isrelatively new and opportunities existwhereby this type of system can be inte-grated in an evolutionary manner in thecurrent program. Incorporating a degree-of-hazard scheme as a component of thecurrent program would reduce transitionaluncertainties that are sure to arise if theentire regulatory system were to be changedabruptly.Are there sufficient data currently availableto apply an appropriate degree-of-hazardclassification system? In which areas will itbe necessary to do basic or targeted re-search before such a system can be devel-oped? Are there substantial problems re-lated to testing techniques, available stand-ards for measurements, and variability ofdata? These questions are now being ex-amined by OTA.What is the most appropriate group for ex-peditiously designing this type of manage-ment system: EPA, private or Governmentresearch groups (e. g., National Bureau ofStandards), or organizations that representseveral interested parties (e. g., consumers,producers, regulators)?

While advocates of a degree-of-hazardclassification and management system agree thatthese questions are important, they argue thatthe current program is inadequate, and suggestthat a degree-of-hazard scheme could be devel-

oped and effectively implemented. The Cali-fornia Office of Appropriate Technology (OAT)study indicates that categorization of industrialwaste is possible and recommends that Depart-ment of Health Services should develop a “cate-gorization scheme for hazardous waste as ameans of linking waste with preferred methodsof treatment and disposal . . .“(37) A recentcost-benefit analysis finds:(39)

. . . that more stringent (and therefore morecostly standards) should be set on the more haz-ardous waste and less stringent standards forthose waste that pose smaller health risks. If oneset of standards is imposed on all types of healthrisks, a serious misallocation of resources willresult with some risks being overregulated, inthe sense that dollars spent elsewhere wouldprovide greater reduction in health risks andperhaps, some hazardous waste risks not beingregulated strictly enough.

Thus the current EPA attitude, supporters sug-gest, should be to encourage rather than discour-age investigation of the concept.

Critics of EPA’s regulations have made thefollowing statements:

●

●

●

●

●

The waste are not categorized by intrinsicproperties that could lead to a hazardoussituation.The criteria for listing waste rely primarilyon measures of genetic impairment andacute toxicity; measures related to mobility,degradability, and long-term exposure areneeded also.Performance standards, as currently pro-posed, do not provide adequate guidelinesfor the uniform application of the permit-ting process.The current approach leads to extensiveregulation of high-volume, low-hazardwaste and inadequate regulation for verylow-volume, but extremely high-hazardwaste.The current regulations do not encourage acost-effective means to control NIHW norto recover components from it, and becauseof its exclusive rather than inclusive orien-tation may actually encourage increased ac-tivity to remove large quantities of hazard-ous waste from regulatory control.

29

2. Can appropriate criteria for hazard classesbe established?

Although specific criteria are proposed for allthe classification methods, the justification forselected criteria has not been provided orthoroughly investigated. Given the paucity ofinformation about the cause-effect relationshipbetween some compounds and environmental orhealth hazard plus the uncertainties surroundingthe extrapolation of data from one species to es-timates of risk for another, skeptics have sug-gested that scientific justifications cannot bedeveloped for a standardized classification sys-tem. The specificity of hazardous conditions andthe extreme diversity of NIHW prevents the de-velopment of realistic guidelines or standardsrelated to a degree-of-hazard approach. In thecurrent climate of decreasing resources, develop-ment of a degree-of-hazard system may producean unwarranted burden for data-collection. Thecurrent program is not yet complete and there islittle justification at this date to discount theeffectiveness of EPA’s approach.

With increasing emphasis on cost-benefitanalyses by EPA and the current administration,supporters of a degree-of-hazard concept main-tain that technical justifications and scientificallybased criteria can and must be developed if thecurrent program is to operate effectively. More-over, establishing boundaries for a classificationsystem would be no different from setting stand-ards (e. g., EPA standards established for permis-sible levels of regulated substances). The task isnot easy, however; it could take several years todevelop a workable system, one that improvesexisting systems. (The current regulatory pro-gram also will take time before it is fullyimplemented, e.g., EPA has suggested it couldbe up to 6 years before facilities receive permits. )The variety of preparatory efforts that are neces-sary include a review of those data currentlyavailable (e. g., chemical, physical, and tox-icological) and those data needed to establish thesystem; evaluations of interrelatedness of datafor classes of compounds; directed research tojustify certain boundaries or criteria for classesof compounds; and development of models ofenvironmental fate and projected health impactsto suit degree-of-hazard evaluations.

The concept of degree of hazard is not new.Assessments of the potential hazard to humanhealth and the environment created by manytypes of materials are required in other en-vironmental regulations (e. g., Clean Air Act;Clean Water Act; Federal Insecticide, Fungicide,and Rodenticide Act; TSCA; and Superfund)and much of the preparatory work discussedabove has been initiated already. In fact, EPAhas explored the possibility of developing ascreening mechanism for compliance with TSCAthat groups new chemical notifications by cat-egories of high, medium, and low risk. (40)Drawing upon the information and data re-quired by these other regulations, the increasedunderstanding of the principles for human andecosystem toxicology, and elements of currentlyproposed classification systems, supporters sug-gest that scientifically justified criteria could beestablished for a degree-of-hazard classificationscheme. These criteria could include the level oftoxicity, safety characteristics, environmentalfate, potential for movement once released tothe environment, and concentrations releasedfrom the disposal facility; the establishment ofthese criteria at the national level would reducemuch of the current uncertainties within theEPA program and could provide continuityamong the State programs.

3. Can the analytical burden inherent i nNIHW management be reduced by a degree-of-hazard approach?

Once any regulatory system is fully im-plemented, generators and disposers will be re-quired to conduct some analytical tests on wastestreams for use in leachate-monitoring activities.These tests include screening tests for chemicaland toxicological properties for a wide range ofcompounds. Skeptics of a degree-of-hazard sys-tem contend that it is unclear whether the ana-lytical and financial capability currently exists toaccomplish the large-scale testing effort that aclassification system could demand, particularlyfor small companies. While it is true that exten-sive testing could be required initially to facil-itate classifying particular waste material, sup-porters of the concept argue that subsequentanalysis required of industry is routine andminor by comparison. Extensive retesting is nec-

30

essary only if and when the industrial processgenerating the waste has been changed or inthose industries using batch processes. Also thedevelopment of adequate analytical capabilitiesis necessary even under the current regulatory

system; the analytical burden imposed on indus-try for delisting a material now judged hazard-ous by EPA is currently substantial (even thoughEPA may not have provided a comparable ana-lytical justification for listing the waste); thussupporters maintain that a degree-of-hazardconcept would net add substantially to the ana-lytical burden. This position, however, is con-troversial.

If a degree-of-hazard system is developed, itwill be necessary to establish analytical criteria(chemical and toxicological) with some care. It isconceivable that the cost of meeting these cri-teria could be greater than actual disposal costsfor small volume or one-time waste generators(i. e., waste generated through cleanup of a proc-ess unit or through accidental upset in the sys-

tem; waste resulting from batch rather than con-tinuous processes where the waste compositionvaries from job to job). Care will be needed todevelop analytical criteria and methodologieswhich are economically and technically appli-cable to these situations as well as to large-scalewaste generation.

Federal and industry efforts to validate data-gathering activities for multiple evaluation ofsimilar waste and similar facilities could reducesome of the costs and eliminate duplication of ef-fort. Considerable effort will be needed to estab-lish accredited laboratories where required testscan be performed. Establishing a network oflaboratories could reduce the economic burdenfor small and large industries alike. Some effortin developing test methodology will be needed.Although test protocols may already be avail-able for analysis in one medium (e. g., water)they generally are not easily transferable toother media (e. g., air or soil).

In its ongoing assessment of nonnuclear in-dustrial waste disposal, OTA will continue itsinvestigation of the advantages and disadvan-tages of degree-of-hazard classification and thepotential for incorporating it into a regulatorypolicy framework. Further evaluation is neededto answer the questions raised here and to iden-tify, if not resolve, the uncertainties that canemerge when developing a classification andmanagement system based on degree-of-hazard,rather than some qualitative use of the conceptonly. Of particular importance is an assessmentof how to implement such a scheme — no t neces-sarily as a replacement, but as a growing compo-nent of the current program. For example, itmay be appropriate to maintain the nationalframework as it currently exists and to incor-porate degree-of-hazard classification in areasdealing with permitting or liability require-ments. Another alternative is to allow theStates, as ultimate managers of the nonnuclearindustrial hazardous waste (NIHW) problem, todevelop degree-of-hazard classification andmanagement systems within their programs. Ifthis were a practical outcome of an implementa-tion analysis, then efforts to develop uniformcriteria within the Environmental ProtectionAgency (EPA) regulations would be desirable.Full implementation of such a system requiresdeveloping a set of technological criteria andtreatment/disposal alternatives for managingthe various classes of waste. The availability ofthese alternatives is another area of some uncer-tainty that requires further investigation.

Figure 4 summarizes those areas that requirefurther research, development, and analysis,and the possible benefits of implementing a Fed-eral hazard classification system for manage-ment of industrial waste. Before a Federal sys-tem can be designed and implemented it will benecessary to develop information about wastegeneration, management needs and options,classification criteria, and policy opportunities,and the costs of obtaining these, Without ad-dressing these information needs and the uncer-tainties surrounding them, the optimistic results

indicated in figure 4 may not occur or classifica-tion could have negative impacts on a nationalwaste management effort. If properly devel-oped, however, a hazard classification systemmight provide a cost-effective means of handlingthe hazards posed by management of industrialwaste. However, an analysis of the current ap-proach and a degree-of-hazard approach isneeded.

The problems and uncertainties of developingand applying a degree-of-hazard classificationand management system to NIHW might be re-solved by combining the interests of the publicfor health protection, the needs of industry, theinitiative of State programs, and the efforts ofthe scientific community, The anticipation of agreater potential for protecting human healthand the environment and long-term economicbenefits provides an important incentive for re-considering this concept as a potentially cost-ef-fective way to manage NIHW.

Development of an efficient managementsystem, whether it follows a classification ap-proach or not, requires that certain factors betaken into account. The system must be de-signed to maximize compliance and must be en-forceable; therefore, it is necessary to considerultimate ease of administration and capabilityfor institutional compliance. If the system un-dergoes frequent and unrealistic changes, tre-mendous problems can result, as was empha-sized by the Conservation Foundation’s reporton low-level radioactive waste disposal. (18)

The proper role of the scientist in definingand classifying . . . waste, now often unclear,frustrating and constantly changing, is also akey element in establishing an administrativelyworkable system. Scientists initially develop theinformation used in promulgating standardsand then are required to comply with and im-plement classification systems that haveemerged from the political process. However,the rules that emerge from the standards-settingprocess may not reflect the actual capability orpractice of those who must comply with them.

31

32

Figure 4.—Research, Development, and Analysis Requirements and Possible Benefits of Implementation of aHazard Classification System

What must be done

1What might result

SOURCE: Off Ice of Technology Assessment.

Finally, resource constraints must be assessed power—are directed toward waste that pose therealistically. A well-designed, cost-effective greatest risks for both the short and long termsmanagement system will make certain that the for human health or the environment.limited resources–whether economic or man-

Appendix: Dangerous Waste Criteria forthe State of Washington

The following description illustrates the catego-rization of one class of waste and suggests methodsfor applying the scheme to waste mixtures. This in-formation was provided by the Department of Ecol-ogy, State of Washington.

WAC 173=303=100 DangerousWaste Criteria

(I) The Dangerous Waste Criteria consist(a)

(b)(c)

(d)

The “Dangerous Waste CharacWAC 173-303-090;

of:eristics,

Toxic Dangerous Waste, WAC 173-303-101P e r s i s t e n t D a n g e r o u s W a s t e , W A C173-303-102; andCarcinogenic Dangerous Waste, WAC173-303-103.

(2) Applicability. Any person who has establishedthat his waste meets any of the Dangerous Waste Cri-teria is a dangerous waste generator, and shall com-ply with the requirements set forth in this chapter forgenerators.

(3) Relation to Lists. The Dangerous Waste Cri-teria shall be the primary means used by the depart-ment to modify the Dangerous Waste Lists set forthunder WAC 173-303-080.

WAC 173=303=101 ToxicDangerous Waste

(1) Purpose. This section describes methods fordetermining the toxicity of a waste and the criteria bywhich a toxic waste shall be designated as a danger-ous or extremely hazardous waste.

(2) Categorization. Table A-1 establishes catego-ries (X, A, B, C, or D) for particular toxicity levels.The X category is the most toxic, and the D categoryis least toxic. Substances which have toxicity levels

Table A-1 .—Toxic Category

Aquatic (fish) ‘Oral (rat) Inhalation (rat) Dermal (rabbit)Category L D50 - ( p p m ) L D5 0 (mg /kg ) L C5 0 ( m g / L ) L D5 0 ( m g / k g )

x - < 0 1 < 0 5 - - <002 -<-2A 0 1 - 1 0 5 5 0 0 2 - 0 2 2-20B 1 10 5 - 5 0 0 2 - 2 2 0 - 2 0 0c 10- 100 5 0 - 5 0 0 2 . 2 0 2 0 0 - 2 0 0 0D 100- 1 000 5 0 0 - 5 0 0 0 2 0 - 2 0 0 200-20,000

—. —

below the D category are generally considered to benontoxic.

(3) Establishing Waste Toxicity. A person shallestablish the toxicity of his waste or waste constitu-ents by applying his knowledge about his waste,and/or by using the following information sourcesand testing methods:

(a) The National Institute for OccupationalSafety and Health (NIOSH) document “Reg-istry of Toxic Effects of Chemical Sub-stances” (Registry);

(b) The U.S. EPA’s regulation 40 CFR table117.3 (Spill Table); and

(c) The bioassay testing methods adopted underWAC 173-303-110 (3).

(4) Book Designation Procedure.(a)

(b)

A person may use the Book DesignationProcedure described in this paragraph onlyif:(i)

(ii)

(iii)

He knows the toxicity categories (as setforth in paragraph (2), above) for thesignificant toxic constituents in hiswaste;He knows the concentrations of thesignificant toxic constituents in hiswaste; andHe can demonstrate to the departmentbeyond a reasonable doubt that anywaste constituents about which he haslimited or no knowledge do not signif-icantly affect the toxicity of his waste.

Equivalent Concentration (E. C.). A personwho is book designating his waste shalldetermine the equivalent concentration (inpercent) of the toxic constituents in his wasteby using the following formula:E.C. (%) = X% + A% + B% + C% + D%

10 100 1,000 10,000where (X, A, B, C, or D) 70 is the sum of allthe concentration percentages for a particu-lar toxic category.

Example 1. A person’s waste contains: Al-drin (X category)-O.Ol%; Diuron (B cate-gory)- l%; Benzene (C category ) -4%;Phenol (C category )-2 %; Cyclohexane (Ccategory )-5 70; Water (nontoxic)— 87%.His equivalent concentration (E. C.) wouldbe:

33

34

E.C. (‘o) = 0.01% + 0% + 1 % + (4% + 2% + 5%) + 0%10 100 1,000 10,000

= 0.01% + 0% + 0.0170 + 0.01170 + 0% = 0.03170

So his equivalent concentration equals0.031%.

(c) Toxic Dangerous Waste Graph. To bookdesignate his waste, a person-shall use theToxic Dangerous Waste Mixtures Graphbelow (fig. A-1) by finding the equivalent

Figure A-1 .—Toxic Dangerous Waste Mixtures

100,000

10,000

1,000

100

10

1

0.1

DW

EHW

0.001 001 0.1 1.0 10 100Equivalent concentration (percent)

concentration percentage for his wastealong the absicissa, finding his total wastequantity along the ordinate, and plottingthe point on the graph where the horizontalline drawn from his total waste quantity in-tersects the vertical line drawn from hiswaste mixture’s equivalent concentration. Ifthe plotted point is in the area markeddangerous waste (DW), he shall designatehis waste as a dangerous waste; if theplotted point is in the area marked extreme-ly hazardous waste (EHW), he shall desig-nate his waste as an extremely hazardouswaste.

DW = dangerous wasteEHW = extremely hazardous waste

SOURCE: E. W. Tower, Solid Waste Management Division, Off Ice of Land Pro-grams, Department of Ecology, State of Washington, Olympia,Wash

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