OVERVIEW OF INDUSTRIAL HYGIENE PRINCIPLES OF EVALUATING WORKER EXPOSURE

1. OVERVIEW OF INDUSTRIAL HYGIENEPRINCIPLES OF EVALUATING WORKER EXPOSURE UNIVERSITY OF HOUSTON - CLEAR LAKE FALL 2013

2. DEFINITION Industrial Hygiene (IH) is the science devoted to the anticipation, recognition, measurement, evaluation, and control of adverse occupational stresses or agents which could cause sickness and impaired health among workers and the community. The basic goal of IH (i.e. occupational hygiene) is to promote a safe and healthful work environment.

3. OCCUPATIONAL HYGIENE The science and art of anticipating, recognizing, evaluating, and controlling health hazards in the workplace. The purpose of this introduction is to provide an understanding of the general principles of evaluating worker exposures in the industrial environment.

4. IH FOCUS 1. Hazardous agents in workplace 2. Health effects associated with excessive exposures 3. Occupational Exposure Limits (OELs) for each agent 4. Workforce organization and staffing 5. Significant sources of exposure; tasks and work procedures involved 6. Control measures

5. IH ELEMENTS • Anticipation • Recognition • Evaluation • Control

6. GENERAL PRINCIPLES • Sequence for decision–making process • Exposure assessment evaluation by qualitative, semi-quantitative, or quantitative methods depending on purpose • Requires feedback from multiple info sources • As part of an effective OH program, info collection, analysis, and decision-making are continuous and simultaneous.

7. ANTICIPATION Expectation of potential health hazards and is generally more difficult for the entry-level, inexperienced occupational hygienist since skills in anticipation generally increase with experience. Ability to recognize potential health hazards as well as knowledge of scientific developments, new technologies, and regulatory requirements, etc.

8. RECOGNITION Requires knowledge and understanding of workplace environmental stresses and effects on health of the worker related to processes and control measures; inventory of chemical, biological, and physical hazards; potential chemical hazards are determined by toxicity and also conditions of use. Involves collection of available information along with the application of IH principles.

9. RECOGNITION Detailed information to be obtained regarding types of hazardous materials used (i.e. inventory), type of job operation, worker exposures and patterns, levels of air contaminants, exposure duration, control measures, etc. Consult product information including MSDSs. Develop workplace characterization which results in defining “exposure groups” for same tasks/similar manner (e.g. chemical, physical, biological hazards, etc. for workers).

10. EVALUATION Involves observation as well as monitoring and use of analytical methods required to detect the extent of exposure; decision-making process resulting in an opinion on the degree of health hazards and/or stressors that exist; determine significance (e.g. subjective/objective judgment); extent of potential health hazards based on comparisons of environmental measurements with current governmental regulations and recommended technical guidelines.

11. EVALUATION • Exposure assessment: initial qualitative method for prioritization; then, semi-quantitative (i.e. mathematical modeling) or quantitative (i.e. monitoring) methodologies. • Air monitoring can be involved for quantitative assessment; breathing zone exposures preferred. • On-going process: feedback from multiple sources of information; refine exposure estimates; evaluate control effectiveness; priorities change! • Initially “dangerous trades” vs. varied issues today.

12. EFFECTIVE EVALUATION • Utilize a multi-disciplinary approach including knowledge-based technical information. Contributions include: occupational hygiene, chemistry, engineering, health physics, medicine, epidemiology, toxicology, and nursing disciplines as well as management and manufacturing expertise. • Integrate knowledge and develop control strategies for potential risk limitation. • Consider team-based efforts of personnel including getting expert opinions from other professionals.

13. EXPOSURE ASSESSMENT • Control exposures • Compliance determinations • Program management (i.e. respiratory; hearing/noise; medical surveillance, etc.) • Epidemiologic studies • Health complaint investigations • Risk assessment • Proposed change evaluations to process

14. CONTROL Involves the reduction of environmental stresses to levels that the worker can tolerate without impairment of health or productivity; various general control methods employed for accomplishments in an efficient and effective manner.

15. CONTROL Defined as the adjustment or regulation of an operation to meet a standard or guideline, the reduction or prevention of contaminant release, and the ability to contain a stressor/hazard.

16. CONTROL METHODS • Engineering – remove the hazard; should be primarily considered. • Administrative – reduce exposures through scheduling/job rotation; housekeeping; employee training; not generally favored. • Personal Protective Equipment (PPE) – use should be secondary to design and implementation of engineering controls.

17. ENGINEERING CONTROLS • Substitution • Change in process • Source modification • Isolation • Enclosure • Wet methods • Ventilation

18. ADMINISTRATIVE CONTROLS EXAMPLES: - Arranging work schedules and the related frequency/duration to limit employee exposures to health hazards. - Transferring employees at PELs to an environment where additional exposure is not anticipated. - Housekeeping; preventive maintenance.

19. ADMINISTRATIVE CONTROLS Administrative controls must be designed only by knowledgeable health and safety professionals, and used cautiously. Not as satisfactory as engineering controls and have been criticized as a means of spreading exposures instead of reducing or eliminating personal exposures.

20. PPE PPE may be used to protect the worker when it is not feasible to render the working environment completely safe. Examples: eye/foot/head protection, gloves, respirators. Considered a secondary control method to engineering and administrative controls and should be used as a last resort.

21. EFFECTIVE IH PROGRAM Applies knowledge to the anticipation and recognition of health hazards arising out of work operations and processes, evaluation and measurement of the magnitude of the hazard based on past experience and study, and control of the occupational hazards.

22. POTENTIAL HAZARDS • Chemical • Physical • Biological • Ergonomic

23. CHEMICAL HAZARDS • Hydrocarbons • Solvents • Oil Mist • Dust (Total and Respirable) • Crystalline Silica • Formaldehyde • Carbon Monoxide • Airborne Fibers

24. PHYSICAL HAZARDS • Noise • Radiation - Ionizing - Non-ionizing • Lighting • Heat/Cold Stress • Pressure Extremes

25. BIOLOGICAL HAZARDS • Bioaerosols • Surface/Bulk Contamination • Tuberculosis • Bloodborne Pathogens • Indoor Air Quality Issues

26. ERGONOMIC HAZARDS • Musculoskeletal Disorders • Cumulative Trauma Disorders • Carpal Tunnel Syndrome • Material Handling/Lifting • Workplace Design Considerations

27. OTHER HAZARDS • Confined Spaces • Waste Management • Lab Health and Safety • Emergency Planning • Etc. . .

28. EXPOSURE ASSESSMENT Determination or estimation of the magnitude, frequency, duration, and route of exposure. • Estimation can be qualitative or quantitatively determined • Defines exposures that occur or anticipated to occur in human populations • Complex task regarding persons and workplace exposures to hazardous substances.

29. FIVE STEPS FOR EXPOSURE ASSESSMENT • Determine purpose and scope of survey • Become familiar with process operations • Perform the preliminary, qualitative survey • Perform workplace monitoring (quantitative evaluation), and • Interpret the sampling results. • Steps can be consecutive or simultaneous!

30. TYPES OF EVALUATIONS • Comprehensive exposure assessment to identify and quantify health hazards • Assess compliance with regulatory standards and/or technical guidelines • Review exposures based on complaints • Exposure assessment for medical and epidemiological studies • Determine effectiveness of engineering and/or administrative controls.

31. COMPREHENSIVE EXPOSURE ASSESSMENT Primary objective is to determine the acceptability of exposures to health hazards for all workers on all days in designated work areas or for specific operations such as batch production, spill response, pilot projects, and maintenance. Based on identification and quantification/estimation of exposures to workplace stressors, then use of walk-through survey procedures for hazard identification and quantification, and subsequently, evaluation techniques to estimate employee exposure levels are employed. Use of databases.

32. COMPLIANCE SURVEY Exposure to stressors are quantified and evaluated by comparison to published health standards, OSHA Permissible Exposure Limits (PELs) or technical recommended guidelines such as American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs). Determine compliance vs. non-compliance.

33. COMPLIANCE • Compliance is acting in accordance with health and safety regulations. • Noncompliance is failure to act as above. • Demonstration of noncompliance requires that an exposure exceed the standard with an acceptable degree of certainty, usually a 95% confidence. • Therefore, maximum risk employees are usually monitored and compared to standard limits. May indicate possible current OH program weakness. • Standards allow re-evaluation related to documentation and rigorous statistics regarding exposures being under control as an incentive.

34. COMPLAINT RESPONSE • Evaluation should include interviews, visit the workplace for walk-through surveys to obtain necessary information. • Recognize that the cause of the health hazard could be different than noted. • At conclusion, inform complainant regarding results to demonstrate that all potential health hazards are seriously considered.

35. MEDICAL AND EPIDEMIOLOGICAL STUDIES • Personnel need to understand worker exposures to evaluate the effect of exposure on workers either individually or as a group. • Past exposure assessed by modeling scheme or on a qualitative, subjective basis. • Quantification of past exposures is difficult. • Exposure information available for epidemiological studies to relate health effects.

36. CONTROL EFFECTIVENESS • Effectiveness of engineering and administrative controls can be assessed separately or as part of a comprehensive exposure assessment. • Example: before and after monitoring related to engineering controls. • Administrative controls perhaps by sampling over time during work practices, etc.

37. PROCESS OPERATIONS • Physical facility layout • Process description and steps • Inventory of process stressors/hazards • Worker job classifications • Worker health status • Control measures in place • Results from past evaluations • Other associated process hazards

38. PHYSICAL FACILITY LAYOUT • Understand general facility layout • Location, terrain, physical arrangement • Examine facility (i.e. blueprints, drawings, diagrams, documents, etc.) • Observe ventilation systems along with existing airflow patterns • Photograph documentation

39. PROCESS DESCRIPTION Information obtained through interviews, personal/visualobservations, technical process information, and record reviews. A walk-through survey is an important methodology to understand, verify, and/or modify documentation; look for potential sources of health hazards and chemical air contaminants and physical agents.

40. POTENTIAL INDUSTRIAL AIR CONTAMINANTS • Welding fumes – metal fumes and oxides, welding rods, coatings, decomposition products, and products of combustion • Combustion products – CO, NOx, particulates • Foundry emissions – Si, oil mist, metals, CO • Smelting – combustion products, metal fumes, SO2, and metals

41. POTENTIAL INDUSTRIAL PHYSICAL AGENTS • Noise – equipment, compressed air, etc. • Ionizing radiation - isotopes, machinery, X-Ray, process controls (levels and thickness) • Non-ionizing radiation – welding, UV energy, thermal IR sources, radar, microwave, etc. • Heat – thermal stresses include furnaces, smelting, casting operations, drying ovens

42. STRESSOR INVENTORY • Hazard/Stressor listing for identification • Chemical and physical agents • MSDSs; Haz Com (29 CFR 1910.1200) • Toxicological information; reference sources • Occupational Exposure Limits (OELs) + e.g. OSHA PELs, ACGIH TLVs, NIOSH RELs, AIHA WEELs, ANSI, NIOSH Pocket Guide

43. TOXICITY VS. HAZARD • Toxicity is the capacity of a material to produce injury or harm to living tissue when the chemical has reached a sufficient concentration at a certain site in the human body. • Hazard is the probability that this concentration will occur within the body; affected by many factor/elements generally related to conditions of use.

44. OCCUPATIONAL EXPOSURE LIMITS (OELs) • Regulatory standard – issued by governmental body (i.e. OSHA) • Voluntary guidelines – published by consensus process (i.e. ACGIH, ANSI); used at discretion of employer • “Local limits” – developed by organizations if stressor is not addressed by regulation or voluntary guidelines (i.e. manufacturer)

45. JOB CLASSIFICATIONS/WORK HEALTH STATUS Formal job descriptions, and personnel interviews with employees/supervisors. Directly observe operations and activities! Worker health status – medical surveillance for health hazard recognition and workplace logs of incidents/injuries/illnesses for assistance with stressor identification.

46. CONTROL MEASURES • Document various control measures used and apparent effectiveness usually through walk-through workplace survey. • Methods of eliminating or minimizing exposures to health hazards. • Examples: LEV, general ventilation; isolation/enclosure; shielding; admin; PPE. • Observe also lack of control measures.

47. PAST EVALUATIONS/IDENTIFY POTENTIAL HAZARDS Review of past occupational hygiene or related evaluations. Determine: time elapsed; process, equipment, or workforce changes, identification of significant problems, and/or other indicators. Personnel interviews and site review. Get workers involved in the familiarization step of a survey to assist with acceptance.

48. POTENTIAL HAZARD ID • Apply fundamentals for hazard identification of the jobs to be evaluated. • Interview personnel for confirmation regarding facilities, chemical, job activities, work procedures, controls and PPE. • Get workers involved in the familiarization step of the survey which will facilitate acceptance of the findings and implementation of recommendations.

49. PRELIMINARY ASSESSMENT - QUALITATIVE Familiarity with process/operation to qualitatively evaluate magnitude of stressors (e.g. chemical and physical hazards) without benefit of instrumentation. Visual observations; use of senses (i.e. smell); inspection of control measures implemented and effectiveness; and, PPE.

50. WORKPLACE MONITORING -QUANTITATIVE EVALUATION Document exposure levels either by measurement or use of semi-quantitative methods. Strategy developed depends on the reason for evaluation. Purpose is FIRST!