introduction to industrial hygiene module 12. 2©2006 teex what is industrial hygiene? industrial...
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Introduction to Industrial HygieneMODULE 12
2 ©2006 TEEX
What is Industrial Hygiene?
Industrial hygiene is the science of anticipating, recognizing, evaluating, and controlling workplace conditions that may cause workers' injury or illness.
Key factors: Employee exposure to hazards Control for hazards to protect workers
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Steps to Protect Employees
Anticipate potential hazards Recognize potential hazards Evaluate exposure and risk Control exposure and risk (Not just for health hazards)
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Hierarchy of Controls
1. Engineering controls: Remove hazard Process change, Chemical substitution Ventilation, Shielding, Guarding Requires little or no employee action
2. Administrative controls: Manage exposure
Worker rotation, Procedures, Training Trench shoring, Controlled access areas Requires employee action
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Hierarchy of Controls
3. Personal protective equipment (PPE) Respirators, Gloves, Boots, Clothing Fall protection equipment, Hard hats Requires individual employee action Last line of defense, behind engineering
and administrative controls Addressed in 29 CFR 1910 Subpart I
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Chemical exposures in oil and gas operations
What chemicals are used in oil and gas operations?
How can employees be exposed? What toxic effects do these chemicals
have? How can employees be protected from
these effects?
Toxic and Hazardous Substances29 CFR Subpart Z
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29 CFR Subpart Z
1910.1000 Air Contaminants: Includes Z tables: worker exposure limits
for specific listed substances Employee exposure cannot exceed limits Tables Z-1, Z-2, Z-3 each have their own
requirements
PEL = Permissible Exposure Limit
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29 CFR Subpart Z
1910.1001-1096: Specific regulations for individual
substances including: asbestos (1910.1001); lead (1910.1025); bloodborne pathogens (1910.1030), and others
1910.1200 Hazard Communication
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1910.1000(a) - Table Z-1
Derived from 1968 ACGIH TLVs American Conference of Governmental
Industrial Hygienists Threshold Limit Values Levels thought to cause no significant
adverse health effects in the majority of the communityCHECK
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1910.1000(a) - Table Z-1
Lists common workplace chemicals Two types of limits:
8-hour Time Weighted Average (TWA) or Ceiling (C) limits
Employee exposure shall at no time exceed a ceiling (C) exposure limit
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1910.1000(a) - Table Z-1
8-hour Time Weighted Averages (TWA) Employee exposure shall not exceed 8-
hour TWA in any 8-hour work shift of a 40-hour work week
Calculations illustrated in (d)
Units: Parts per million (ppm) Milligrams per cubic meter (mg/m3)
Subtitles & TransitionsFOR EXAMPLE…
5 mg/M3,
Respirable fraction
15 mg/M3,
Total dust
Particulates not otherwise regulated (PNOR)
1 ppmChlorine
50 ppmCarbon monoxide
1000 ppmAcetone
Ceiling8-hr TWASubstance
Table Z-1 Examples
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1910.1000(b) - Table Z-2
Adopted from ANSI standards (American National Standards Institute)
Expanded standards developed for some of the substances found in Z-2, including: Benzene 1910.1028 Cadmium 1910.1027 Formaldehyde 1910.1048 Methylene chloride 1910.1052
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1910.1000(b) - Table Z-2
Table Z-2 expresses exposure limits as: 8-hour TWA Ceiling Peak
If a substance has both ceiling and peak limits: peak = level never to be exceeded
Exposure levels over the ceiling but under the peak must comply with margin notes in table
TWA must still not be exceeded
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1910.1000(b) - Table Z-2 Examples
10 min500 ppm300 ppm200 ppmToluene
5 min in any 3 hrs
600 ppm200 ppm100 ppmStyrene
10 min50 ppm20 ppmHydrogen sulfide
10 min50 ppm25 ppm10 ppmBenzene
NotesPeakCeiling8-hr TWA
Substance
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1910.1000(c) - Table Z-3
8-hour TWA limits for forms of silica Adopted from ACGIH TLVs
SiO2 : basic component of sand, granite
Quartz: 2nd most common mineral Quartz sand (crystalline silica) used to
fracture rock formations in wells Silica in barite, lignite, and bentonite
mud additives
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Health Effects of Silica
Silicosis Irreversible but
preventable Most commonly
associated with silica dust
Other possible effects: Lung cancer Some auto-immune
diseases
(Scanning electron micrograph by William Jones, Ph.D., compliments of OSHA)
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1910.1000(c) - Table Z-3
5 mg/m3Respirable dust
15 mg/m3Nuisance dust
30mg/m3
% Sio2 Amorphous
10mg/m3
% Sio2 + 2
Crystalline Silica(Respirable fraction)
PELSubstance
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1910.1000(d) – Computation formulae
Time Weighted Average E = (C1T1 + C2T2 + …)/total time
Total time used = 8 hours Example in § 1910.1000(d)(1)(ii) What about different work schedules?
Varies by chemical Most chemicals: Worst 8 hours of shift Lead: adjusted by hours worked Interpretation – Foulke letter, 1997
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1910.1000(d) – Computation formulae
Exposure to Chemical Mixtures Em = (C1/L1) + (C2/L2) + … + (Cn/Ln)
If Em > 1, employee is overexposed
Assumptions: Chemicals’ effects are additive Dose is proportional to C T
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1910.1000(e) – To achieve compliance
Administrative or engineering controls first wherever feasible
When those are not feasible for full compliance: protective equipment or other protective measures
Equipment or technical measures must be approved by competent industrial hygienist or qualified person
Respirators: 1910.134
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Chemical-Specific Standards
1910.1001 Asbestos 1910.1018 Inorganic Arsenic 1910.1025 Lead 1910.1026 Chromium (VI) (revised 2006) 1910.1027 Cadmium 1910.1028 Benzene
Oil and gas drilling, production, servicing exempt
1910.1029 Formaldehyde
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1910.1020 Access to employee exposure and medical records
Employees, representatives, and OSHA have right of access
Preserved for 30 years, with exceptions Employee consent for medical records OSHA access order posted if
identifiable Trade secrets Employee information
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1910.1030 Bloodborne Pathogens
Occupational exposure: Reasonably anticipated skin, eye, mucous
membrane, or parenteral contact With blood or other potentially infectious
materials (OPIM) e.g. certain body fluids, tissues
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1910.1096 Ionizing radiation
OSHA standards cover NORM and TENORM
Exposures must be kept within limits even if sources are natural
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1910.1201 Retention of DOT markings, placards and labels
Retain markings on packages received until clean enough to remove hazard
Freight container or vehicle retains placards until materials removed enough
Readily visible Non-bulk packages not to be reshipped:
Hazard Communication labels OK
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1910.1450 Hazardous chemicals in laboratories
For laboratory use only Supersedes other standards in Subpart
Z – except: PELs Prohibition of eye and skin contact
Exposure monitoring and medical surveillance for those over action levels
Protective MeasuresOther Standards and
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General Duty Clause
Recognized hazards may be cited If there is no PEL:
Consensus or proprietary standards ANSI, ACGIH, AIHA
Industry Best Practices Manufacturer Recommendations (MSDS)
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Biological Hazards
Potentially infectious material exposure Contagious diseases e.g. influenza Vector-borne diseases e.g. Malaria,
Lyme disease Fungi e.g. mold, spores Toxins e.g. endotoxin Allergens / sensitizers e.g. pollen, red
cedar
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Physical and Radiological Hazards
Heat or cold (General Duty Clause) Vibration (General Duty Clause) Noise (1910 Subpart G) Non-ionizing radiation (electromagnetic,
light) (1910 Subpart G) Ionizing radiation
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Other Standards
29 CFR 1926 Subpart D: Occupational Health and Environmental Controls Construction operations only
API RP 54 Noise rules allow for 12 hour shifts Handling drilling fluid chemicals and
additives
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Protective Measures
How are exposures to health hazards evaluated on your site?
How are they controlled?