health hazard assessment in system safety …health hazard assessment in system safety evaluation...
Post on 17-Mar-2020
2 Views
Preview:
TRANSCRIPT
Health Hazard Assessment in System Safety Evaluation
Part 2 Chemical Risk Assessment
International System Safety Society Training Symposium August 4, 2014
Mark Geiger, MS, CIH, CSP, CIH Naval Safety Center Liaison Office Mark.Geiger1@navy.mil 703 695-4703
Rodney Simmons, PhD, CSP, The Petroleum Institute, Abu Dhabi, United Arab Emirates
rod_simmons@me.com
Tutorial Health Hazard Assessment Time Topics Comments
0800-0850 • Introduction and Overview
• Health hazard assessment process
• Physical hazards
• Relevance of health hazard assessment to the systems engineering process
• Focus areas – why worry • Ergonomic and physical hazards
0900-0950 • Chemical hazards
• Background • Preliminary Hazard Identification • Exposure and Risk Assessment • Controls • Sources of Information
1030-1130 • Noise overview
• Exercises in health hazard assessment
-Noise the most prevalent occupational health hazard- it can be evaluated and often controlled Health hazard assessment of a single hazard (noise, physical agent or chemical)
2
Importance of Chemical Risk Management • The production and use of chemicals is fundamental to all
economies. – Global chemical business > $1.7 trillion per year. – U.S. chemicals
• $450 billion business • Exports > $80 billion per year.
• Chemicals directly or indirectly affect our lives and are essential to our food, our health, and our lifestyle.
• Important chemical information necessary to protect people and the environment – Hazardous properties of chemicals, – Control measures, – Allows the production, transport, use and disposal of
chemicals to be managed safely. • Source A Guide to The Globally Harmonized System of Classification and Labelling
of Chemicals (GHS) https://www.osha.gov/dsg/hazcom/ghs.html#3.2
3
Health Hazard Evaluation Part 2
• Outline of the Mil Std 882 Task 207 Health Hazard Assessment Process
• Background material needed to evaluate “chemical” hazards
• Application of the Health Hazard Evaluation Process to chemical materials/processes
• Links to process improvement and systems engineering (time permitting)
• Additional information (in background materials)
4
Task 207 Health Hazard Analysis Process
1. Purpose-Perform and document a health hazard assessment to identify human health hazards
– Evaluate proposed hazardous material and processes
– Propose measures to eliminate hazards • Or to reduce risks when the hazards can’t be
eliminated
5
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
Task 207 Health Hazard Analysis (HHA) Process
2. Task Description: Perform and document HHA including potential effects from exposure to hazards -What is a health hazard- a condition inherent to operation, maintenance, storage, transport, use or disposal that can cause death, injury, acute or chronic illness, disability or reduced job performance
6
Mil Standard 882 Task 207 Health Hazard Analysis (HHA) Process
Three (3) Categories of Information a. Hazard identification –name and affected system components and
processes (where it’s occurs) b. Start with chemical inventory and process description
1. Exposure pathway- how people can be exposed to include mode of transmission (inhalation, absorption, ingestion)
2. Exposure characterization –level of energy or concentration- what type of models can be used?
3. Sometimes the evaluation will be quantitative (versus qualitative) c. Severity and probability of exposures
- Describe the potential acute and chronic health risks Use information to develop d. Mitigation strategy for each hazard
– Describe a target mitigation strategy for each hazard based on the degree of risk reduction
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
7
Very Limited Toxicology Introduction
• Dose-response
• Target organs and mechanism of actions
• Chemical and physical properties
• Standards and their limitations
• HHA Process • Background material • Chemical Health Hazard Evaluation • Mitigation/control
8
Dose-response ~ exposure – effect
Threshold (limited effect) Where is this point? It differs among people
Saturation Variables include • Prior exposures • Individual sensitivity • Limitations of exposure evaluation • What’s an acceptable response or risk
Threshold (limited effect) Generally considered “safe” for members of working population
9
Target Organs and Mechanism of Actions and Routes of Entry
• Target organs – affected body systems • Mechanism of actions- how system is affected • Routes of Entry – how the toxic material reaches the
target
Substance Target Organs
Route of Exposure or entry
Mechanism of Action
Symptoms/ effects
Solvent Skin Contact Defat cracking peeling contact dermatitis
Solvent Liver Respiration Cellular injury
Cirrhosis, Cancer?
Solvent Central Nervous system
Respiration, contact
Not fully known
Dizziness, “intoxication Long term Central Nervous system (CNS) impacts
• HHA Process • Background
material • Chemical Health
Hazard Evaluation • Mitigation/control
10
Target Organs and Mechanism of Actions and Routes of Entry
• Target organs – affected body systems • Mechanism of actions- how the toxin acts • Routes of Entry – how it reaches the target
Substance Target Organs
Route of Exposure or entry
Mechanism of Action
Symptoms/ effects
Carbon Monoxide
Red blood cells
Inhalation (also smoking and some chemicals)
Competitive bonding with oxygen on red blood cells
Diminished ability to transport oxygen
Carbon Monoxide
Central Nervous System (CNS)
Respiration, contact
Decreased oxygen availability
Headache, diminished cognitive ability, unconscious's, brain damage, potential death 11
Chemical properties and physical properties
State of matter affects potential routes of entry • Dusts • Fumes • Mists
• Aerosols • Fibers • Vapors • Gases
• HHA Process • Background
material • Chemical Health
Hazard Evaluation • Mitigation/control
12
Physical Hazards
13
Explosives Flammable Gases Flammable Aerosols Oxidizing Gases Gases under Pressure Compressed Gases Liquefied Gases Refrigerated Liquefied Gases Dissolved Gases Flammable Liquids Flammable Solids Self-Reactive Chemicals
Pyrophoric Liquids Pyrophoric Solid Pyrophoric Gases Self-heating Chemicals Chemicals, which in contact with water, emit flammable gases Oxidizing Liquids Oxidizing Solids Organic Peroxides Corrosive to Metals Combustible Dusts
Slide courtesy of OSHA Training Institute
Types of Chemical Hazards • Acute Toxicity • Skin Corrosion/ Irritation • Serious Eye Damage/ Eye Irritation • Respiratory or Skin Sensitization • Germ Cell Mutagenicity • Carcinogenicity • Reproductive Toxicity
– Single Exposure – Repeated Exposure
• Aspiration • Simple Asphyxiants
18 Slide courtesy of OSHA Training Institute
• HHA Process • Background
material • Chemical Health
Hazard Evaluation • Mitigation/control
Lower Flammable Limits (LFL) Relative to Occupational Exposure Limits
Chemical TLV (1) IDLH (2) LFL Acetone 500 ppm 2500 ppm
(10% of LFL) 2.5% (25,000 ppm)
Ammonia 25 ppm 300 ppm 15% (150,000 ppm)
Formaldehyde 0.75 ppm (OSHA PEL)
20 ppm 7 % 70,000 ppm)
28
(1) Threshold Limit Value (TLV)- recommended standard developed by the American Conference of Governmental Industrial Hygienists (ACGIH)
(2) IDLH Immediately dangerous to life and health Lesson: A combustible gas meter does not indicate safety relative to inhalation exposures. Readings are in percent of Lower Flammable Limit (LFL), also often described as the Lower Explosive Limit
Odors – What does the nose know? This reflects initial information, not an
approved sampling method. Beware of olfactory fatigue.
Chemical TLV(1) ppm (2) Odor threshold (ppm)
Benzene 10 (OSHA PEL – 1 ppm)
31
Chloroform 10 200 Formaldehyde 1 1 Sulfur dioxide 5 5 Acetone 500 40 Chlorine 1 0.001
(1) Threshold Limit Value (TLV)- recommended standard developed by the American Conference of Governmental Industrial Hygienists (ACGIH)
(2) Parts per million concentration in air (v/V - volume/Volume) 29
Occupational Exposure Standards and their Limitations
• Sources of data – Human experience – Environmental effects – Laboratory Toxicology – comparison with animal data – Comparison with similar chemicals
• Many new or limited use chemical don’t have established occupational exposure standards
• Purposes of standards – Prevention of long-term health effects – Prevention of cancer and/or reproductive effects – Prevention of acute irritation and discomfort – Some combination* 30
• HHA Process • Background
material • Chemical Health
Hazard Evaluation • Mitigation/control
Occupational Exposure Standards and their Limitations
• Sources of standards – National regulatory US OSHA/European Union – Consensus – American Conference of Governmental
Industrial Hygienist Threshold Limit Values ®
• Intent – May or may not consider economic feasibility • Standards may be national/local, but scientific data
is typically international • Limitations- Individual variability and susceptibility
• Standards are not a fine line between safe and unsafe • Shortcomings in standards development, state of science and
regulatory processes
31
• HHA Process • Background
material • Chemical Health
Hazard Evaluation • Mitigation/control
Occupational Exposure Standards Commonly used in the US
Permissible Exposure Limits, PELs • OSHA’s legally allowed
concentrations in the workplace • Three types:
– 8-hr TWA – PEL – Ceiling – PEL – STEL – PEL
• Tend to be chronologically dated
– Process for update is cumbersome and highly politicized
32
Threshold Limit Values, TLVs • Airborne concentrations of
substance to which it is believed that nearly all workers may be repeatedly exposed, day after day, without adverse effect
• Guidelines published annually by American Conference of Governmental Industrial Hygienists (ACGIH)
• Tend to be more up-to-date and conservative
• More consistent with other national standards
Mil Standard 882 Task 207 Health Hazard Analysis (HHA) Process
Three (3) Categories of Information a. Hazard identification –name and affected system
components and processes (where it’s occurs) b. Start with chemical inventory and process description
1. Exposure pathway- how people can be exposed to include mode of transmission (inhalation, absorption, ingestion)
2. Exposure characterization –level of energy or concentration- what type of models can be used?
3. Sometimes the evaluation will be quantitative (versus qualitative)
c. Severity and probability of exposures - Describe the potential acute and chronic health risks
d. Mitigation strategy for each hazard
– Describe a target mitigation strategy for each hazard based on the degree of risk reduction
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
33
Health Hazard Analysis (HHA) Process First steps in Hazard Assessment
Step 1. Hazard identification –name Chemical inventory is the first step
Step 2. Use chemical safety data to evaluate potential risks - Affected system components: - Related impacts
Step 3. Processes Evaluation • Where material occurs • How its used • Potential for release/exposure
• Some information may be provided by Mil Std 882 Task 108 Hazardous Material Management Plan Task 201 Preliminary Hazard List
• Additional information from similar legacy systems
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
34
Health Hazard Analysis (HHA) Process Next step in Hazard Assessment
Use the chemical inventory (i.e. Hazard identification) And hazard chemical hazard information to evaluate - Processes (where its occurs) - Affected system components - Related impacts • Some information may be provided by Mil Std 882
Task 108 Hazardous Material Management Plan Task 201 Preliminary Hazard List
• Additional information from similar legacy systems
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
35
36
• Required by OSHA and EPA Regulations and common sense
• Should be part of systems engineering process
– Suggest making this a contract deliverable – Consider compatible data formats and link to user training
• Chemical safety information – Material Safety Data Sheets (MSDS) – Safety Data Sheets (SDS) being phased in – Other sources of information (see background slides) – DOD sources of information (HMIRS)
http://www.dlis.dla.mil/hmirs/
• Prevention through design where feasible – use least hazardous processes and materials compatible with effectiveness and economy
Chemical Inventory (what and where used)
Severity and probability of exposures Applies to all categories of health hazards
Chemical example used
• Basic process evaluation • Where and how exposures are likely to occur • Anticipated severity of exposures
– Initial qualitative – Quantitative, if warranted by initial assessment
• Discussion of calculating estimated airborne exposure, time permitting
37
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
Health Hazard Analysis (HHA) Process Mil Standard 882 Task 207
1. Exposure pathway- how people can be exposed to include mode of transmission (inhalation, absorption, ingestion)
2. Exposure characterization –level of energy or concentration- what type of models can be used?
- Simple - Sometimes the evaluation will be quantitative (versus
qualitative) - More complex (many mathematical models, many
derived from the ideal gas law) - Past evaluations of similar processes
- Sources include Service Public Health Centers and NIOSH 38
39
Why Estimate Chemical Concentration and Exposures?
• Preliminary estimate of risk in initial design and development.
• Potential application to chemical process management
• Disaster evaluation and response • Background information for system safety
professionals- How to use this information – Generally safe situation (Okay-Yes) – Significant uncontrolled hazard (Not okay-stop) – Areas requiring further evaluation (Get help-Maybe)
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
40
Estimating chemical concentration and exposures
• Tools for estimating airborne chemical concentrations and their dispersion.
• Potential application to chemical process management – Including routine maintenance and – Predictable mishaps (disaster prevention and
response planning) • Assist system safety professionals in integrating
chemical risk management into the systems engineering process
Calculation of Chemical Concentrations
If time permits
41
Mitigation System Safety Hierarchy of Controls
Control Measure Examples Eliminate hazards through design selection
Removal of critical hazardous product (such as lead or chrome from paints); aerobic versus anaerobic digestion for waste (no H2S)
Reduce risk through design alteration
Use less hazardous materials; dip or brush paint application
Incorporate engineered features or devices
Local exhaust ventilation; process temperature controls
Provide warning devices
Temperature/pressure warning devices Gas concentration monitor
Signs, procedures, training protective equipment
Warnings, qualifications/training for use, personal protective equipment
42
• HHA Process • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
Risk Evaluation May lead to mitigation strategy
• Begin with the end in mind- what is this process or operation seeking to accomplish? – Many legacy processes have used unnecessarily
hazardous material and approaches – Examples of process substitution
• Remote inspection of confined spaces (versus manned entry) • Water-based versus oil-based paints in some marine or damp
areas • Replace versus refurbish some parts • Glove box paint removal versus hand sanding
• Databases and sources of assistance – EPA Green Chemistry http://www2.epa.gov/green-
chemistry – Service public health centers and systems command
environmental directorates – Industry and trade groups
43
• HHA Process • Background material • Chemical Health Hazard
Evaluation • Mitigation/control
Ventilation Basics- Factors to Consider • Lack of any ventilation in a space
• Volume of airflow • Fire and explosive safety • Health hazards • Comfort and removal of nuisance contaminants
• Source of contaminants • Specific point source –consider local exhaust • Diffuse sources – general dilution ventilation
• Direction of airflow – Will prospective contaminants be moved away from workers?
• Air balance – make up air (and its distribution) • Ventilation system design for
– Efficiency –complex duct design and/or excessive air duct velocity wastes energy
– Noise control- excessive noise may be a sign of wasted energy – Maintainability - Fire-explosive safety
44
45
Personal Protective Equipment Considerations in Routine Use
• Need to describe operations and requirements for protective equipment in writing
• Identify alternatives to personal protective equipment to be used when feasible.
• Guidelines for routine selection and use. • Documented training in routine and emergency
use. • Limitations and liability for proper use. • Monitoring and enforcement of use. • Comfort and productivity.
• HHA Process • Background material • Chemical Health Hazard
Evaluation • Mitigation/control
46
Comfort and productivity
A man in armor is his armor’s slave
- Robert Browning
Quoted in: Personal Protective Equipment for Hazardous Materials Incidents: A selection guide NIOSH 1984
47
Personal Protective Equipment (PPE) Considerations in Emergency Response
• Added problems of protective equipment selection and use – Uncertain exposures – Limited time for planning
• Limits of Protective Equipment
– Inhalation exposures – Skin exposures
• Added burden of PPE when performing work
– Heat stress – Discomfort – Reduced mobility, manual dexterity and visibility
•
48
Always think of skin (protection) first!
49
Early history of skin protection Early model: Water-permeable
skin prevents wandering away from the swamp.
Latter model: Non-permeable skin prevents drying out and is difficult for predators to chew.
50
Evolution of Advanced Protective Equipment
Technical problems: Additional protective equipment limits
mobility and increases heat stress. (Still can’t get away from the swamp).
51
Common materials which can create exposures via the skin
Chemical(s) Use Remarks Aniline and related dyes Dyes and stains
Diazinon Malathion
Pesticides Many pesticides absorbed via skin
Dinitrobenzene Dyes, organic synthesis
Formaldehyde Preservative Skin sensitizer
Hydroquinone Photo developer Skin sensitizer
Mercury Inorganic form in instruments
Organic forms highly toxic
Phenol Separatory media for DNA isolation, organic
synthesis, disinfectants
Nitroglycerin Ordnance, propellants Potent vasodilator, acute headaches, cardiac issues
52
Gloves and other protective equipment selection
• Required part of OSHA standard for protective equipment, respiratory protection and hearing conservation – 29 CFR 1910.132
• Aspect of systems support related to training and support equipment
• Should consider permeability, protection and durability of gloves – See vendors websites such as Best Gloves – http://www.chemrest.com/
53
May be well prepared for respiratory hazard
Not so well-prepared for potential skin hazards
Simplified Case Study- Extrusion of propellant for rocket manufacture
Common Sources of information include • Process review and hazardous material identification from standard
practice guides • Surveys of similar processes/operations/ work environments
• NIOSH Health Hazard Evaluations
• EPA studies conducted in collaboration with DOD (Example) Handbook on the Management of Ordnance and Explosives at Closed, Transferring, and Transferred Ranges and Other Sites • http://www.epa.gov/swerffrr/pdf/IFUXOCTTHandbook.pdf
54
HAZMAT evaluation- Identify the HAZMATs Blue Shows Mil Std 882 process
• How the HAZMAT is used for each process or
component: – Extrusion into propellants
• Additional considerations: – Temperature during casting – Clean-up of machinery
• Estimate the usage rate of each HAZMAT for each process or component: – Used to evaluate concentrations – minimize explosive
risks and also estimate airborne concentrations. • Recommend the disposition for each HAZMAT (to include
hazardous waste) identified). • Potential substitutions
55
• HHA Process (review)
• Background material • Chemical Health Hazard
Evaluation • Mitigation/control
Simplified Case Study- Extrusion of propellant for rocket manufacture
(Blue shows Mil Std 882 Process) • Process review and hazardous material identification from standard
practice guides: Material used and health concerns • 2,4-Dinitrotoluene C7H7N2O4 Exposure can cause
methemoglobinemia, anemia, leukopenia, liver necrosis, vertigo, fatigue, dizziness, weakness, nausea, vomiting, dyspnea, arthralgia, insomnia, tremor, paralysis, unconsciousness, chest pain, shortness of breath, palpitation, anorexia, and loss of weight.
• Immediate concerns: Explosive safety and related precautions to
prevent detonation – Least hazardous available product selected to accomplish military
objectives – Facility located at safe distance as determined by type and quantity of
ordnance – Explosion proof lighting and control of ignition sources
56
• HHA Process (review) • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
2,4-Dinitrotoluene C7H7N2O4
Physical state and appearance: • Yellow crystals with characteristic odor Physical danger: • Dust explosion possible if in powder or granular form, mixed with air. Chemical dangers: • May explode on heating. The substance decomposes on heating
producing toxic and corrosive fumes including nitrogen oxides even in absence of air. Reacts with strong bases, oxidants and reducing agents.
Occupational Exposure Limits (OELs): • TLV: ppm; 0.2 mg/m3 (as TWA) (skin) (ACGIH 2013). Routes of Exposure: The substance can be absorbed into the body by • Inhalation, • Through the skin • Ingestion.
57
2,4-Dinitrotoluene C7H7N2O4 CAS # 121-14-2 Inhalation risk:
• Evaporation at 20°C is negligible; a harmful concentration of airborne particles can, however, be reached quickly.
Effects of short-term exposure: • The substance irritates the eyes and the skin. The substance may
cause effects on the central nervous system, cardiovascular system, and the blood , resulting in the formation of methaemoglobin. The effects may be delayed.
Effects of long-term exposure or repeated exposures: • The substance may effect the central nervous system, cardiovascular
system and blood , resulting in formation of methaemoglobin.
Information Source: International chemical safety cards http://hazard.com/msds/mf/cards/file/0727.html 58
Methemoglobin • Methemoglobin (British English: methaemoglobin) (pronounced "met-
hemoglobin") is a form of the oxygen-carrying metalloprotein hemoglobin, in which the iron in the heme group is in the Fe3+ (ferric) state, not the Fe2+ (ferrous) of normal hemoglobin. Methemoglobin cannot bind oxygen, unlike oxyhemoglobin.[2] It is bluish chocolate-brown in color. In human blood a trace amount of methemoglobin is normally produced spontaneously. But when it is present in excess the blood becomes abnormally dark bluish brown. The NADH-dependent enzyme methemoglobin reductase (diaphorase I) is responsible for converting methemoglobin back to hemoglobin.
• Normally one to two percent of a person's hemoglobin is methemoglobin; a higher percentage than this can be genetic or caused by exposure to various chemicals and depending on the level can cause health problems known as methemoglobinemia.
59 http://en.wikipedia.org/wiki/Methemoglobin
Some additional considerations
• Temperature of material • Ventilation
– Volume and direction of airflow • Skin protection –
– Approaches to minimize manual contact • Ordnance manufacture is a repetitive
process – Evaluate the potential for ergonomic issues
and repetitive motion disorders 60
• HHA Process (review) • Background material • Chemical Health
Hazard Evaluation • Mitigation/control
Summary Chemical risk assessment considers
– Materials • Composition and chemical properties • Hazardous constituents and their potential health and safety
impacts • Potential substitutes, if appropriate
– Process description – Risks during routine use, maintenance, realistic
minors “spills”, emergency scenarios – Control measures using the hierarchy of controls;
• substitution/ elimination; • containment/control; • procedures and training; • protective equipment (consider limitations)
61
Break
• Please return at 10:30
• Next – Noise, the most prevalent health hazard – Class exercises in health hazard evaluation
• Also available in class handouts – Calculations of solvent and compressed gas
concentrations (time permitting) – Other sources of information
62
Additional Resources
63
64
• Merck Index • Clinical Toxicology of Commercial Products • Chemical Hazards in the Workplace (Proctor and
Hughes) • Sigma Aldrich Library of Chemical Safety Data • Physicians Desk Reference (for drugs) • Hazardous Chemicals Desk Reference (Lewis) • Emergency Care for Hazardous Materials Exposure
(Bronstein and Currance)
Additional Library Resources
65
• EPA Chemical References http://www.epa.gov/enviro/html/emci/chemref • ChemView http://java.epa.gov/chemview • Allows comparative evaluation of materials and public access
to varied data sources. • Read the manual! • http://java.epa.gov/chemview/resources/ChemView%20Public
%20UI%20Guide.pdf • MSHA Link to MSDS sites http://www.msha.gov/MSDS.HTM
• OSHA/EPA Occupational Chemical Database.
https://www.osha.gov/chemicaldata/
• CAMEO Chemicals An online hazardous material database
http://response.restoration.noaa.gov/cameochemicals
Internet Resources
66
More Resources
• NIOSH Pocket Guide to Chemical Hazards • http://www.cdc.gov/niosh/npg/default.html • OSHA Annotated PELs • Also contains other reference guidance • https://www.osha.gov/dsg/annotated-pels/tablez-2.html
• ACGIH® 2014 Threshold Limit Values for Chemical Substances in
the Work Environment. Adopted by ACGIH® with Intended Changes. See http://www.acgih.org/.
• The Globally Harmonized System for Hazard Communication • https://www.osha.gov/dsg/hazcom/global.html
67
• Primarily for transportation accidents
• Cross reference – UN Numbers – Common names – Standard response
guides – Evacuation distances
North American Emergency Response Guidebook
http://phmsa.dot.gov/hazmat/library/erg
Navy Marine Corps Public Health Center http://www.med.navy.mil/sites/nmcphc/industrial-hygiene/Pages/Industrial-Hygiene-Topics.aspx
68
Chemical Stressors Chemical Stressor Dictionary with Occupational Exposure Limits and Other Information and Notations- Quick reference for determining current occupational exposure limits and information such as carcinogenicity classification, reproductive notations, and skin notations, for specific chemical stressors of industrial hygiene interest. Chemical Stressors List with Medical Surveillance and BEI Information and Skin Notation–Reference for determining the medical surveillance procedure requirements for chemical stressors. It also provides a listing of chemicals that fall under specific medical surveillance programs (Medical Matrix Number). Emerging Contaminants Program Emerging contaminants (EC) are defined by the Department of Defense (DoD) as chemicals or materials that either lack published health standards, have an evolving regulatory or science status or pose a threat to human health or the environment with the potential to impact mission readiness. The program is managed under the Assistant Deputy Under Secretary of Defense for Environment, Safety and Occupational Health as delineated in DoD Instruction 4715.18, Emerging Contaminants (EC). As an active member of the Chemical and Material Risk Management Directorate’s Materials of Evolving Regulatory Interest Team (MERIT),
Additional Resources • Scorecard • Cancer references • http://scorecard.goodguide.com/health-
effects/references.tcl?short_hazard_name=cancer
69
Back-up slides
70
71
• Chemical inventory • Terms (review) • Emergency Response
Guide • Material Safety Data
Sheets (MSDS) • Safety Data Sheet (SDS) • Other Chemical Safety
information
Routine and emergency access to chemical safety information
• HHA Process • Background
material • Chemical Health
Hazard Evaluation • Mitigation/control
72
• Consider integration into systems engineering and documentation
• Emergency response guidelines • Pocket References
– NIOSH pocket guide – DOT Guide – Emergency Handling of Hazardous
Materials (OSH office) • Material safety data sheets MSDS)/ • Safety Data Sheets (SDS)
– Vary widely in usefulness – May need to develop summary information – DOD databases
Sources for locating chemical safety information
• OSHA is retaining the requirement to include the American Conference of Government Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) on the safety data sheet (SDS) in the revised Standard. OSHA finds that requiring TLVs on the SDS will provide employers and employees with useful information to help them assess the hazards presented by their workplaces. In addition to TLVs, OSHA permissible exposure limits (PELs), and any other exposure limit used or recommended by the chemical manufacturer, importer, or employer preparing the safety data sheet are also required.
73
Occupational Exposure Standards on Safety Data Sheets
74
Background Information
• Conversions, spills and other yucky stuff – Common conversions – Ideal gas law (college chemistry)
• Sources of information on chemical compatibility – Prevention - How to keep things from going
wrong – Mishap evaluation - How to figure our what
might have gone wrong (after the fact)
75
Conversions Avoid Mars Polar Lander Type Impacts
• Metric English (SAE) • Mass Moles Vapor volume
Concentration (in a given volume) • Logarithms Linear (exponential
relations) • Handy conversion factors
•http://www.greatdreams.com/lander.htm
76
Some useful conversion factors
Metric English
28.3 liters 1 cubic foot(a little more than 1 mole ofgas at STPD)
3.785 liters 1 gallon
1 kg 2.2 pounds
77
Sample conversion problem
• How much does a gallon of acetone weigh? • 1 gallon (water) x 0.79 density (acetone/water) x 3.78 liters/gallon x 1.0 kg/liter x 2.2 pounds/gallon = = 6.57 lb./gallon acetone • 1 gallon water x 3.78 liters/gallon x 1.0 kg/liter x 2.2 density pounds/kg = 8.32 lb./gallon of water
Math check • 1 gallon of acetone weighs 6.57 pounds (2.99 kg) = 0.79 • 1 gallon of water weighs 8.32 lb. (3.78 kg)
78
Sample problem: Boyles Law Application
• A smelter is to be located at 8000 feet altitude.
• Find the volume correction if the pressure is 650 mmHg (versus 760 mmHg at sea level)
• The fan used to exhaust contaminant is sized for 10,000 cfm.
• How large a fan will this location require?
79
Sample problem: Boyles Law Application
• PV=Constant or P1V1=P2V2
P1V1 = P2V2
• V2 =P1V1/P2
• V2 = 760 mmHg x 10000 cfm/650 mmHg =
• V2 = 11692 cfm
Ground level - higher pressure, lower volume
Altitude- lower pressure,
greater volume
80
Sample problem: Boyles Law Application
• How much nitrogen will a 10 cubic foot cylinder hold if the pressure is increased to 2200 psig? (standard for a compressed gas cylinder).
• Normal atmospheric pressure is 14.7 psig.
• Could this form an asphyxiating mixture if
released into an un-ventilated room 10 feet x 12 feet x 8 feet?
(Combustible range in air is between 4% and 75% by volume; Explosive range 18.3 to 59 %).
81
Sample problem: Boyles Law Application • PV = constant* or P1V1=P2V2
* (at constant temperature) • Normal atmospheric pressure is 14.7 psi. V2=P1V1/ P2 = 2200 psi x 10 cf/14.7 psi V2=1497 cf Nitrogen conc. =1497 cf/[10 ft. x 12 ft. x 8 ft.] 1497 cf Nitrogen /960 cf room size Nitrogen conc. = 1.5* >> 0.04 (4%) This is enough to occupy to room volume 1 ½ times Room size 10 feet x 12 feet x 8 feet
82
Now a more exciting variant- Hydrogen Sample problem: Boyles Law Application
• PV = constant* or P1V1=P2V2 * (at constant temperature) • Normal atmospheric pressure is 14.7 psi. V2=P1V1/ P2 = 2200 psi x 10 cf/14.7 psi V2=1497 cf hydrogen conc. =1497 cf/[10 ft. x 12 ft. x 8 ft.] 1497 cf hydrogen/960 cf room size Hydrogen conc. = 1.5* >> 0.04 (4%) This is enough to occupy to room volume 1 ½ times Room size 10 feet x 12 feet x 8 feet Hydrogen Lower explosive limit, LEL, is 4%
83
Charles Law: Correction for Temperature
• The same cylinder may be subjected to increased pressure as a result of heat.
• The sprinklers are activated at 121 oC (250 oF). • Will this prevent rupture?
• If rupture disks are designed to give way
at 3000 psi, what temperature will this represent?
84
Portable Compressed Gas Cylinder Safety Web page for the health and safety of everyone on campus, presented by The University of Texas Health Science Center at Houston Safety Council and the Office of Institutional Advancement
Remainder of the nitrogen gas cylinder after it exploded. Laboratory damage resulting
from a gas cylinder explosion.
Other Issues and Thoughts • Should electrical equipment be explosion proof?
– Always consult NFPA and other codes.
• Effectiveness of room ventilation
• Could a smaller cylinder be used?
• For remotely located/confined areas consider – Locating the tank outside the space and having gas
piped in – Use of a smaller tank
85
86
Charles Law: Correction for Temperature (continued)
• V/T = constant (at unchanging pressure)
• V1/T1 = V2/T2 If external pressure is constant – T2= V2 T1 /V1= [273+121]x3000psi/2200psi – T2 = 394 oKx3000psi/2200psi =537 oK
• Temperature 0C: 537 oK-273 = 264 0C • Temperature 0F: 264 0C x 9/5 oF/oC + 32oF = 507 0F
• Conclusion: Sprinklers will go off before rupture disks
burst. • Note that “real” fire prevention calculations may be a little
more complicated.
87
Sample Problem: Avogadro’s Number
• V = n x Constant • V= volume, n= moles of gas • At standard temperature and pressure (25 0C, 298 0K) Volume of a gas is proportional to the number of molecules (regardless of the
type or molecular weight of the gas)
Avogadro’s constant = 1 mole ~ 6.023 x (10)23 molecules At STPD one mole of gas occupies about 24.45 liters Hydrogen H2 (MW =1.008) or Oxygen O2 (MW = 32.00)
would occupy the same volume (24.45 liters ~0.86 cubic feet)
88
Ideal Gas Law
• N = number of moles • T = Temperature (absolute temperature in
Kelvin or Rankin) • P = Pressure (absolute pressure) • V = Volume • R = gas constant (depends on units used)
89
Ideal Gas Law
• PV = nRT • V = nRT/P • V = 24.45liters @ STPD
• v/Vroom = n(moles)25/V
room
– P= pressure – V= volume – n= number of moles – R=gas constant – T= temp. (Kelvin)
Limitations • Volatility/rate of
evaporation • Ventilation • Direction of airflow • Position of worker • Skin absorption • Non-linear
properties of some gases (CO2)
90
Sample calculation using ideal gas law to predict solvent exposure
• One liter of acetone* spills within a room 6 m x 8 m x 3 m
(Approximately 20 feet x 25 feet x 10 foot ceiling)
• Assuming rapid and complete evaporation, what will the maximum airborne concentration be?
* Volatile solvent previously used in nail polish remover and many ordnance operations.
* Update provided by Dr. Simmons: Current formulations of nail polish remover use ethyl acetate mixed with isopropanol. http://www.cutexnails.com/nail-care-products/no-spill-pump/ingredients
91
Sample calculation using ideal gas law to predict solvent exposure
• V(solvent vapor) = n x 24.45 l/mole * • V(solvent vapor) = 1 liter x 790 g/liter x 1mole/44 gram x 24.45 liter/mole
v (solvent vapor) = 439 liters = 0.00305 = 0.3% V (Volume of room) = 6 m x 8 m x 3 m = 144 m3x
1000l/m3
v/V = 439 liters = 0.3%= 3050 ppm 140,000 liters
v/V = 0.00305 x 106 = 3049 ppm>>750 ppm* *(occupational exposure limit)
x [ 106 for ppm conversion]
92
Sample calculation using ideal gas law to predict solvent exposure
V(solvent vapor) = 439 liters = 0.00305v/V = 0.3% V (room)* = 144000 liters = 0.00305 = 0.3% = 3049 parts per million (ppm) ** >> 500 ppm (Threshold Limit Value) >> 750 ppm Short-term exposure limit (STEL) (15 minutes) *V (Volume of room) = 144 m3x 1000l/m3
– 0.00305 x 106 = 3049 ppm>>500 ppm (occupational exposure limit)
** x [ 106 for ppm conversion] • The bad news – solvent concentration is much
greater than occupational exposure standard. • The good news – solvent concentration is below the
lower explosive limit 1% • Caution – you would need to apply a safety factor of
4 to 10 depending on your level of caution and extent air mixing
93
Gas Laws - Summary and Applications Boyle’s Law PV=
Constant
The volume of a gas at fixed temperature is inversely proportional to the pressure
Correction for volume if pressure changes
Charles' Law V/T = constant
Volume of a gas at constant pressure is proportional to the temperature
Correction for gas volume with temperature
Avogadro's Law
V = constant x n
Volume of a gas at constant pressure and temperature is proportional to the number of moles of gas
Calculate number of moles of a substance to estimate volume and/or concentration in a given space
Ideal gas law PV=nRT Volume occupied and pressure exerted by a gas is related to heat energy
Calculate gas concentration based on number of moles present.
94
Calculation of maximum concentrations
• Can combustion of an Acrylon® carpet produce a lethal dose of hydrogen cyanide?
• Step 1 Find the fraction of HCN by mass, Acrylon® has an empirical formula of polymer (polyacrylonitrile) – Polymer (C3H3N)x
– Monomer Empirical formula C3H3N – Structural formula CH2=CH-CN
• Step 2 Identify the dose level of concern
– You are told that a lethal dose of hydrogen cyanide is 300 mg HCN/Kg air when inhaled
– If this was the lecture on toxicology or a real-life problem, you might have to find this data independently
95
Can combustion of an Acrylon® carpet produce a lethal dose of hydrogen cyanide?
• Step 3 Find the dimensions of concern and the concentration of Acrylon® in the carpet.
• [i.e. composition and quantity of reactive precursor material] – The room is 12 x 15 x 8 feet – The carpet measures 12 x 15 feet and contains 30 oz. of Acrylon®
per square yard – Assume that the yield of HCN is 20% and that the carpet is 50%
consumed
96
Molecular weight calculations Element Atomic
Weight Number of atoms
Mass
C 12 X 3 = 36 H 1 X 3 = 3 N 14 x 1 = 14
Molecular weight of CH2CHCN ∑ 53 C 12 X 1 = 12 H 1 X 1 = 1 N 14 x 1 = 14
Molecular weight of HCN ∑ 27
97
Molecular weight calculations
Molecular weight of HCN = 27 = 0.509 Molecular weight of CH2CHCN 53 Bad news Up to 51% HCN by weight of Acrylon® may be released if
the carpet is entirely consumed Good news (this is just a calculation) Actual reaction yield is likely to be well below 100%
98
Estimate the amount of hydrogen cyanide potentially formed
0.509g HCN x 3 yd. x 5 yd. x 30 oz. Acryl on® x 0.5 faction consumed 1.000g CH2CHCN =0.509 x 15 yd. x 30 oz. x 28.4 g/oz.* = 6505 g = 6.5 kg HCN released in room Density of air is 1900 g/m3*
Room size = 12ft x 15 ft. x 8 ft. =1440 ft3
1440 ft3 x 1 m3/28.4 cu = 50.70 m3 (53.3 yd3)
6505 g HCN = 241 g HCN/M3 air = 90.1 g HCN/m3 air**
1900 g/M3 air x 50.7 M3 >> 300 mg HCN/kg air IDLH = 50 ppm ~ 47 mg/m3 TLV = 5 mg/m3 (1.9 kg/M3 air x 38 M3)/ 1 kg/1000 g • See notes for conversions • ** Actual yield likely to be only 20% 18 g HCN/m3 air “only” 18000 mg/m3
99
Estimate the amount of hydrogen cyanide potentially formed
0.509g HCN x 3 yd. x 5 yd. x 30 oz. Acryl on® x 0.5 faction consumed 1.000g CH2CHCN =0.509 x 15 yd. x 30 oz. x 28.4 g/oz.* = 6505 g = 6.5 kg HCN released in room Density of air is 1900 g/m3*
Room size = 12ft x 15 ft. x 8 ft. =1440 ft3
1440 ft3 x 1 m3/28.4 cu = 50.70 m3 (53.3 yd3)
6505 g HCN = 241 128 g HCN/M3 air = 90.1 g HCN/m3 air**
1900 g/M3 air x 50.7 M3 >> 300 mg HCN/kg air IDLH = 50 ppm ~ 47 mg/m3 TLV = 5 mg/m3 (1.9 kg/M3 air x 38 M3)/ 1 kg/1000 g • See notes for conversions • ** Actual yield likely to be only 20% 18 g HCN/m3 air “only” 18000 mg/m3
• CORRECTED SLIDE
100
Spills and Worst Case Calculations [How bad could it be?]
• Maximum concentration in a given (confined) area
• Limitations (and K factors)
• Saturation calculations
• Steady-state situations
101
Decay Curves [How soon will it get better?]
• Ct= C0e-λt
• Ct concentration at a given time, t • C0 = initial concentration • Λ = rate of change per unit time (example air changes per hour)
• t = time e = natural log 2.71
• Rate of change x log e = log C0 – log C
102
Decay Curves [How soon will it get better?]
• From a prior problem • Concentration of acetone = 0.0078 x10-6 = 7831 ppm
• Ct= C0e-λt
• If the ventilation provides 5 air changes per hour, what will the concentration be after one hour?
• Ct = 7831 ppm x (2.71)-5 = 7831 ppm x 0.0069 • Ct = 53.6 ppm << TLV 750 ppm • Response to this emergency may be to cut off
electrical systems (spark producers) and keep the ventilation operating for a couple of hours
103
Concentration Decay Curves [How soon will it get better?]
Air changes
Ct Ct % change
0 1 1.00000 0
0.5 0.607456739 0.60746 -39
1 0.36900369 0.36900 -63
2 0.136163723 0.13616 -86
3 0.050244916 0.05024 -94.98
5 0.006841535 0.00684 -99.32
10 4.68066E-05 0.00005 -100.00
104
• Required by OSHA and EPA Regulations and common sense
• Should be part of systems engineering process – Suggest making this a contract deliverable – Consider compatible data formats and link to user
training • Emergency Response
– Planning should identify realistic scenarios • What could plausibly go wrong?
• Prevention through design where feasible – use least hazardous processes and materials compatible with effectiveness and economy
Chemical Inventory (what and where used)
105
Estimating chemical concentration and exposures
• Background information – Basics to begin (before you reach for the calculator) – Conversions, spills and other yucky stuff – Ideal gas law (college chemistry)
• Tools for estimating airborne chemical concentration and their dispersion. – Preliminary worst case estimates – Dispersion in closed room – Concentration in steady-state situations – Limited information on dispersion modeling for
outside exposures
106
Basics –before you start from the beginning and/or reach for the checkbook
• Process review and hazardous material identification from standard practice guides
• Surveys of similar processes/operations/ work environments – NIOSH Health Hazard Evaluations – Industrial hygiene evaluation from service public health centers
(Example Navy BUMEDINST 6270.8A, Obtaining Health Hazard Assessments).
– Related industrial setting/ contractors
• Obvious control measures (containment, process selection and management) – Protective equipment and skin protection – Early warnings and general indicators – Especially from similar operations
107
More Basics –before you reach for the calculator
• Process review and hazardous material identification
• Obvious control measures (containment, process selection and management)
• Protective equipment and skin protection • Early warnings and general indicators
108
Considerations for Solvent Spills Ideally, in the planning phase
• Initial concerns for fire and explosion – Flammability
• lower and upper explosive limits • Flash point
– Consider vapor pressure
• Projection of inhalation exposures – Quantity of material used – Characteristics; Toxicity, volatility, warning properties – Ideal gas law to estimate exposures
• Emergency Response (and its limitations)
Content of Material Safety Data Sheets
(MSDS) and
Safety Data Sheets (SDS)
109
The revised Hazard Communication Standard (HazCom 2012) requires that the information on the SDS be presented using specific headings in a specified sequence.
Safety Data Sheets Similar to Material Safety Data Sheets
Provide a good outline of necessary chemical and physical safety information
The SDS format is the same as the ANSI standard format which is widely used in the U.S. and is already familiar to many employees.
Slide courtesy of OSHA Training Institute
111
The format of the 16-section SDS should include the following sections: Section 1. Identification Section 2. Hazard(s) identification Section 3. Composition/information on ingredients Section 4. First-Aid measures Section 5. Fire-fighting measures Section 6. Accidental release measures Section 7. Handling and storage Section 8. Exposure controls/personal protection Section 9. Physical and chemical properties
Slide adapted from the OSHA Training Institute
The format of the 16-section SDS should include: Section 10. Stability and reactivity Section 11. Toxicological information Section 12. Ecological information Section 13. Disposal considerations Section 14. Transport information Section 15. Regulatory information Section 16. Other information, including date of preparation or last revision
112 Slide adapted from the OSHA Training Institute
Safety Data Sheet
SDSs are prime sources of information on health hazards.
Slide adapted from the OSHA Training Institute
113
114
• Required by OSHA and EPA Regulations and common sense
• Should be part of systems engineering process – Suggest making this a contract deliverable – Consider compatible data formats and link to user training
• Emergency Response – Planning should identify realistic scenarios
• What could plausibly go wrong?
• Prevention through design where feasible – use least hazardous processes and materials compatible with effectiveness and economy
Chemical Inventory (what and where used)
HAZMAT evaluation- Identify the HAZMATs’
• Quantity, characteristics, and concentrations of the materials
• Source documents, such as Material Safety Data Sheets (MSDSs), vendor’s information
• Material hazards, including hazardous waste, and determine associated risks. (See MSDS/SDS) – Acute health, chronic health, carcinogenic, contact,
flammability, reactivity, and environmental hazards. • How the HAZMAT is used for each process or component
– Estimate the usage rate of each HAZMAT for each process or component
• Recommend the disposition for each HAZMAT • Potential substitutions
115
top related