Introduction to Exposure Assessment Strategies and Statistics (Part 1 Basic Overview)

Exposure Assessment Strategies Committee 2

Efficient and Effective IH Programs

• A well-rationalized IH program relies on a thorough understanding of what is known, and what is not known • The better the industrial hygienist understands exposures, the better he or she is able to direct and prioritize the IH program CONCEPTS FROM (AKA AIHA SAMPLING STRATEGY MANUAL) 4

Exposure Assessment

• The process of defining exposure profiles and judging the acceptability of workplace exposures to environmental agents 5

Professional Judgment • Vital for identifying similar exposure groups • Necessary for designing sampling strategies • Essential for judging exposures • Important for choosing health hazard control strategies

…..but what is “Professional Judgment?” 6

Why is Exposure Assessment Important? • Growing number of real and perceived risks that industrial hygiene programs must be prepared to manage • Programs in the past were less rigorous, now they must be thorough, systematic, well-documented and efficient Is required by 10 CFR 851, Worker Safety and Health Program, (ref. 851.21, Hazard identification and assessment and Appendix A6, Industrial Hygiene 7 Exposure Assessments • Exposure Assessments are used to: – Understand, prioritize, and manage exposures – Identify exposures that need better characterization, or careful routine tracking – Focus worker training programs – Target medical surveillance programs – Define PPE requirements 8

Exposure Assessment

• Exposure Assessment is a judgment (3 categories): – Acceptable health risk – Unacceptable health risk – Uncertain health risk 9

Comprehensive Strategy

• Comprehensive strategy: directed at assessing all exposures for all workers on all days • Why? Exposures occur whether we are there or not! EXPOSURE ASSESSMENT STRATEGIES 1. Start 2. Basic Characterization 3. Exposure Assessment 4. Further Information Gathering 5. Health Hazard Control 6. Reassessment 7. Communications and Documentation

Reminder baseline, surveys, and periodic resurveys and/or exposure monitoring is required "as appropriate" by 10 CFR 851 - Appendix A6 Start

Qualitative Basic Assessment Characterization (BC)

Exposure Sampling & Risk Quantitative Assessment Assessment (ERA)

Applying Correct Exposure Level Of Response Management & Controls (EMC) SIMPLIFIED EXPOSURE STRATEGY FLOW 1. Set Decision Criteria

2. Document Qualitative Exposure Judgment

3. Gather Samples Of Exposures

4. Statistical Analysis Of Sampling Data (Quantitative Exposure Judgment)

5. Identify Needed Controls

6. Compare Qualitative And Quantitative to Calibrate/Continuously Improve Judgments. Basic Characterization

The Qualitative Assessment

We Are Here EXPOSURE DECISION CRITERIA

• Decision Statistic  Decided early in process  Match up with organization’s risk tolerance  Needed confidence in decisions  95th percentile compared to OEL?  UTL 95%, 95%  Higher confidence higher cost, sometimes unattainable • Occupational Exposure Limits (OEL) HOW DO I NEED TO ARRANGE ASSESSMENTS? SIMILAR EXPOSURE GROUP (SEG) • Why Use SEG? • Engineering controls

• HR Job Title? • Administrative factors

• Comparable job tasks • Same geographical area? • Agents in work environment •Data Driven!!!!! • Work habits

• Machinery WHAT DATA DO I NEED TO COLLECT? DATA TO COLLECT FOR BASIC CHARACTERIZATION • Who, What, Where, When, Why, How

• Who are the employees covered by this assessment

• What job/task/SEG was assessed

• What frequency is the job/task done

• What were weather/environmental conditions

• Where was the job/task located

• Where was equipment

• When: date/time of your assessment DATA TO COLLECT FOR BASIC CHARACTERIZATION • Why is the assessment valid/representative of the job/task

• Who, What, Where, When, Why, How regarding Controls and PPE in use

• Document your judgment of the exposure.  AIHA Exposure Category 0-4 Initial Rating & 1-3 Certainty Level  Or 5 by 5 table ranking Document why/how you reached your judgment AIHA Categories For Grouping and Prioritization

SEG Exposure Control Category** 0 (<1% of OEL) Your decision is made on 1 (<10% of OEL) where you think the th 2 (10-50% of OEL) exposure’s 95 percentile as % of the 3 (50-100% of OEL) OEL falls

4+ (>100% of OEL, Multiples of OEL; e.g., based on respirator APFs) Exposure Risk Assessment

Sampling & Quantitative Assessment

We Are Here DATA TO COLLECT FOR SAMPLING & QUANTITATIVE ASSESSMENT • What type of sample (Personal, Area) • Who was sampled

• Was it valid/representative of the job/task • Employee activity during sample

• Was the sample conducted correctly • Frequency of job/task

• What was the job/task • IH Equipment used

• Where was the job/task • Weather/Environmental Conditions

• Date/time of sample • PPE in use

• Length of sample • Document your judgment of the exposure.  AIHA Exposure Category 0-4 Initial Rating • Length of shift & 1-3 Certainty Level RESULTS FROM INDUSTRIAL HYGIENE SAMPLES • Results of lab analysis

• What type of analysis was done

• Was it lab void

• Limit of detection

• Was the lab accredited

• Date/time sample sent to lab

• Date/time sample received from lab

How do you plan on getting results into the data management system? Exposure Management & Controls

Applying Correct Level Of Response Start

Basic Characterization

AIHA’s Systematic Exposure Categorization & Risk Controls Model Assessment

Exposure Management & Controls Exposure Management & Control Categories

SEG Exposure Control Applicable Management/ Controls Category** 0 (<1% of OEL) no action

1 (<10% of OEL) procedures and training, general hazard communication 2 (10-50% of OEL) + chemical specific hazard communication, periodic exposure monitoring,

3 (50-100% of OEL) + required exposure monitoring, workplace inspections to verify work practice controls, medical surveillance, biological monitoring, 4+ (>100% of OEL, + implement hierarchy of controls, Multiples of OEL; e.g., monitoring to validate respirator protection factor selection, based on respirator APFs)

** - Note: Decisions are made on the exposure’s percentile compared to the OEL at a level that fits the organization’s risk tolerance level. Decision statistic = 90th, 95th, 99th percentile. % OEL • Exposure/OEL * 100 = %OEL • Example 35/100 *100 = 35% OEL • Can be used to simplify analysis • Helps normalize data (noise, extended shift)

• Example: Ethyl Bromide • Using ACGIH TLV 5 PPM as OEL • Results 1.23 PPM TWA? or • 24.6 % OEL (Easy to convey results) Geometric Standard Deviation (GSD) • GSD helps identify variability in data • Basic tool to measure if data is similar • Rule of thumb GSD of 2.5 or greater is overly variable Systems Approach Towards Improving Judgments & Calibrating The Industrial Hygienist IH Exposure Judgment Biases • Research shows exposure judgments of IH’s are inaccurate when statistical tools are not used! – Judgments biased lower than actual exposure

That means under-protection for workers!

– This fact is Worse when comparison to X95th is used

Welcome to the Dart Throwing Monkey ≥ IH concept IH EXPOSURE JUDGMENT

• Statistical tools make exposure judgments better

• Use of rules of thumb increase accuracy and decrease bias

• Documenting decision rationale, yields better judgment

• Move from under estimating exposure judgments towards judging the true exposure Thank you for your time

Questions

Thank You! End Of Meeting 1 (Basic Overview) Homework: Use some of your unsampled tasks to create a Basic Characterization. Try to create an Exposure Risk Assessment using your sampling data. Try using AIHA Categories