Introduction to Industrial Hygiene MODULE 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
3©2006 TEEX Steps to Protect Employees Anticipate potential hazards Recognize potential hazards Evaluate exposure and risk Control exposure and risk (Not just for health hazards)
4©2006 TEEX 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
5©2006 TEEX 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
6©2006 TEEX 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 Substances 29 CFR Subpart Z
8©2006 TEEX 29 CFR Subpart Z 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
9©2006 TEEX 29 CFR Subpart Z : Specific regulations for individual substances including: asbestos ( ); lead ( ); bloodborne pathogens ( ), and others Hazard Communication
10©2006 TEEX (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 community CHECK
11©2006 TEEX (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
12©2006 TEEX (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/m 3 )
Subtitles & Transitions FOR EXAMPLE… 5 mg/M 3, Respirable fraction 15 mg/M 3, Total dust Particulates not otherwise regulated (PNOR) 1 ppmChlorine 50 ppmCarbon monoxide 1000 ppmAcetone Ceiling8-hr TWASubstance Table Z-1 Examples
14©2006 TEEX (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 Cadmium Formaldehyde Methylene chloride
15©2006 TEEX (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
16©2006 TEEX (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
17©2006 TEEX (c) - Table Z-3 8-hour TWA limits for forms of silica Adopted from ACGIH TLVs SiO 2 : basic component of sand, granite Quartz: 2 nd most common mineral Quartz sand (crystalline silica) used to fracture rock formations in wells Silica in barite, lignite, and bentonite mud additives
18©2006 TEEX 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)
19©2006 TEEX (c) - Table Z-3 5 mg/m 3 Respirable dust 15 mg/m 3 Nuisance dust 30mg/m 3 % Sio2 Amorphous 10mg/m 3 % Sio2 + 2 Crystalline Silica (Respirable fraction) PELSubstance
20©2006 TEEX (d) – Computation formulae Time Weighted Average E = (C 1 T 1 + C 2 T 2 + …)/total time Total time used = 8 hours Example in § (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 Interpretation
21©2006 TEEX (d) – Computation formulae Exposure to Chemical Mixtures E m = (C 1 /L 1 ) + (C 2 /L 2 ) + … + (C n /L n ) If E m > 1, employee is overexposed Assumptions: Chemicals’ effects are additive Dose is proportional to C T
22©2006 TEEX (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:
23©2006 TEEX Chemical-Specific Standards Asbestos Inorganic Arsenic Lead Chromium (VI) (revised 2006) Cadmium Benzene Oil and gas drilling, production, servicing exempt Formaldehyde
24©2006 TEEX 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
25©2006 TEEX 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
26©2006 TEEX Ionizing radiation OSHA standards cover NORM and TENORM Exposures must be kept within limits even if sources are natural
27©2006 TEEX 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
28©2006 TEEX 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 Measures Other Standards and
30©2006 TEEX 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)
31©2006 TEEX 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
32©2006 TEEX 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
33©2006 TEEX 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
34©2006 TEEX Protective Measures How are exposures to health hazards evaluated on your site? How are they controlled?