Inhalation Monitoring Data Collection Guidelines July 1, 2002 

### Developed by the US. Environmental Prot ection

**Agency~** 

### Office of Pollution Prevention and Toxics (OPPT)/Economics, Exposure , and Technology Division (EETD)/Chemical Engineering Branch (CEB) INTRODUCTION At times, inhalation monitoring or sampling data may be requested to help OPPT to better evaluate the health risk to employees for substances covered under the Toxic Substances Control Act (TSCA). To help ensure that the appropriate data is received to allow OPPT to conduct its review and to minimize the need for additional efforts on the part ofthe submitter, CEB has prepared the following guidance on developing an inhalation monitoring study protocol prior to conducting monitoring. If monitoring has already been completed, improvements or additions may need to be made to the final report so that OPPT can evaluate it in the proper context. Incomplete protocols and /or results may not be adequate for OPPT to fully evaluate exposures or exposure potential, and may require additional work on the part of the submitter. Although a comprehensive exposure assessment is not needed or required by OPPT, keep in mind that all monitoring studies should ideally fit within the structure ofa larger exposure assessment plan and a complete industrial hygiene program. This document is intended to provide general guidance to environmental, safety, and health professionals in conducting monitoring studies to assess inhalation exposure concerns. It does not cover all individual situat ions or special circumstances. Monitoring studies should be undertaken by a qualified individual who has been trained in the evaluat ion and control ofworkplace exposures. Use the following outline and questions to assist in the development ofthe inhalation monitoring study protocol: A. Objective ofthe Monitoring Study: Clearly describe the objective ofthe monitoring study.

• What are the final data results sought through this study? • What are the exposures ofconcern? • What is the target population ofworkers? • Is t he study designed to assess acute or chronic exposures? This will affect the pattern and duration of sampling, and also possibly the media used to collect the samples. • Is the objective to determine average or worst-case exposures to the substance? If the data are fro m a previous study, the purpose ofthe original data collection or study may have been different than the current objective.

• Was personal monitoring conducted in a way that will give an accurate picture regarding exposure to the substance ofconcern, particularly ifthe origin al purpose ofthe monitoring study was different? • Ifthe purpose ofmonitoring was different, such as prompted by a specific, unrelated incident, was the monitoring method one which will accurately characterize the exposures curr entlyunder evaluation? For example, are long-term exposures (months or years), sh ift-long exposures , or short-term exposure (15 minutes or less) of the greatest interest in evaluating exposures? • Although not necessary for OPPT purposes, it may be useful to consider how the objective of this monitoring study fits logically into a larger exposure assessment framework for the workplace. As noted in the introduction, any individual sampling plan or objective should be part of a larger exposure assessment strategy for the entire workplace. This exposure assessment should include identifying all workplace hazards, developing si mi lar employee

exposure groups, conducting baseline exposure monitoring and/or modeling studies where necessary to characterize the hazards , using follow-up monitoring and/or modeling as needed to

confirm compliance with relevant exposure thresholds, and evaluating exposures using both the

results and professional judgement. B. Sampling Strategy/Sampling Methods: Describe the sampling plan and methodology. • Is the sampl i ng method one that has been validated by an independent organization (i.e, the National Institute of Occupational Safety and Health (NIOSH), the Occupational Safety and

Health Administration (OSHA), the American Society for Testing and Materials (ASTM),

etc.)? • What sampl i ng media or direct reading instrument will be used? What is the strategy that will be used for sample collection, including sample location, flow rates , sampling time, and sample replica t ion? • Will enough samples be taken to ensure that the results are statistically signi fi cant for the population of concern? · • Will a worst-probable or a random sampling strategy be employed? Guidance on Developing a Sampling Strategy A number of strategies and methodologies have been developed to determine the appropriate number of samples that are necessary to estimate exposure profiles for specific tasks. Although models have been developed to assist with this task, professional judgement is important in determining the appropriate number of samples to be taken. Before considering the number of samples needed, identify and categorize the major types of processes to be evaluated and the different types of job tasks associated with each of these processes. Worker groupings by

specific job t asks are commonly referred to as similar exposure groups (SEGs).1 Once the

major processes, job tasks , and similar exposure groups have been outlined, s p ecific sampling can be planned. Four sample groups or types should be identified and considered for the sampling strategy: 1. Identify the group of employees at the greatest risk of exposure from each of the exposure groups or job tasks to be evaluated and collect samples from this group to assess likely maximum exposures. 2. Identify locations in which to conduct process sampling (sometimes referred to as sampling) to map possible worker exposures in and around relevant process equ: This may help to identify one or more SEGs where maximum exposures are li'occur. 3. Randomly select workers for personal monitoring in the defmed SEGs in order to determine typical or average exposures in these groups (please see section below, 

### "The Importance of Random Sampling", for more information on random sample selection). 4. Where relevant, be sure to identify and select workers in non-routine (i.e., maintenance activities) for personal monitoring to determine likely worst-case and typical exposures for these activities. Note: Sometimes it is not possible to determine a maximum risk exposure group. If this is the case, random sampling techniques should be used for sample selection in all similar exposure groups and for process sampling. 

### Determining the Number of Samples to Collect It is important to determine the appropriate number of samples needed
· to get statistically significant results from a sampling study. The number of samples needed will depend on a number ofdifferent factors, including the objective ofthe monitoring study, the characteristics ofthe SEG (e.g. degree ofhomogeneity), and the actual measured levels ofexposure relative to an occupational exposure limit (OEL) or threshold of concern. A Strategy for Assessing and Managing Occupational Exposures, published in 1998 by the American Industrial Hygiene Association (AIHA), recommends that samples should be collected up to a statistical point of diminishing returns for each samp le type or similar exposure group. According to this strategy, statistics show that there will be a point at which additional samples will not significantly improve confidence in t he overall results. Assum ing a normal population distribution and us ing at-table, the maximum value derived from taking additional samples is reached after about 6 to 10 measurements within a defined SEG. Typically , at least six measurements should be taken for each SEG to ensure with sufficient confidence that exposures for the SEG have been adequa tely characterized. (If initial measurements demonstrate that exposures are far less than 10% ofthe threshold ofconcern or higher than the actual thresho ld of concern, fewer measurements may be needed)

. . For exposures very near the threshold of concern or OEL, more than six measurements will likely be needed to determine that exposures are, in fact, consistently below the threshold ofconcern (up to 10 or more measurements). Professionaljudgement should be used to make this determination, taking into account factors such as the cost of additional sampling relative to the cost ofcontrols to limit exposures, and the level of statistical confidence in the results that is desired or needed.2 The chart below shows the increased confidence achieved by increasing the number of samples taken: 

### Effect of Sample Size on Est imating Population Mean and S tandard Deviation3s o c I "0 At - 1) D E! · 10 -o 5 tO Numw of Sample s **--------.-~U~ppe:rcoolldenca** lirm z : 11 1 : . i i i ; ; ,, . cemral o:s'!iit aiB " lower cooftdei'IO!t lln11 2 8 10 12 16 Number of Sa mpl e.•

## If A Minimum Level of 90% Confidence in Sampling Results 

### is Desired Ifit is desired or necessary to obtain at least 90% confidence that maximum exposures are accurately characterized by the sampling results for a particular SEG, regardless of exposure monitoring or control costs, the following table can be used to estimate the minimum number ofsamples that will be necessary to achieve this level ofstatistical certainty

0 This table is published by NIOSH in their Occupational Exposure Sampling Strategy Manual, Chapter 3 

### (1977) 0 Ifthe number of workers in a SEG is known, the table provides the number of samples required to ensure with 90% confidence that at least one individua l among those with the highest 10% ofexposures for that SEG is contained in the sample set. As indicated above, however, additional samples over 10 within a single exposure group may not provide a great deal of additional confidence in the results and may result in siginificant additional sampling costs and time to complete the sampling study

0 Professional judgement should be used to determine cases where more than 10 samples are necessary to evaluate exposureso4 

### Size ofPartial Sample for Top 10% Exposure at a Confidence Level o£0.905 Size of group Number of Required N Samples 

### 8 7 9 

### 8 10 9 11-12 10 13-14 11 15-17 12 18-20 13 

### 21-24 14 25 -29 15 30-37 16 38-49 17

50 18 

### The Importance of Random Sampling If it was not possible to detem1ine an individual employee or group of employees withmaximum risk for exposure, random sample selection techniques s hould be employed. Often , this can be difficult given real - world constraints, but in general, the use of ce rt ain sample selection techniques will improve the likelihood that the samples collected a c curately characterize the exposure variability within an SEG. To conduct random sampling , sampling incidents should be chosen at random first by date , then by shift , and then by worker . During random sampling, samples should not be conducted in clusters (i.e., such as over a one - week period) , but over a longer period of t ime. This period oftime should be long enough to adequately capture exposure variability, bu t not so long that it affects the completion of the sampling study within a reasonable period of time. Multiple dates for sampling should be selected with no consideration for any particular conditions or events that could affect worker exposures. After multiple sampling dates are chosen, mul t iple work shifts, where applicable, and multiple workers must also be sampled to fully characterize exposure variability and reduce bias in the results. Random sampling may be especially difficult for non-routine operations such as maintenance work. However, creative approaches can sometimes be used to conduct random sampling for these types of tasks. Examples include using a shorter sample time, or using a combination of full-shift sampling along with measurements from direct reading instruments.6 C. Laboratory Analysis/Analytica l Method: Describe where the laboratory analysis was conducted and what analytical chemistry method was used. • Has the analytical method used been validated by a third party (e.g., was a specific NIOSH, OSHA, or ASTM method used)? • Is the laboratory accredited by a relevant industrial h ygiene organization, such as the AIHA? • What types of analytical methods are used by the laboratory to ensure accuracy and precision (e.g., how many analyses are conducted of the same extract of a collected sample)? • If applicable, what type of specific direct reading instrument(s) were used for monitoring , and why? What is the level of detection, accuracy, and precision that can be obtained from this

type of instrument? D . Quality Assurance: Discuss the number of samples collected, how many shifts and workers were sampled, how these shifts and workers were selected for inclusion, how the samples were stored after collectio n , and how they were transported to the laboratory for analysis. • Were steps taken for quality assurance purposes (i.e., were blank samples or spiked samples sent to the laboratory along with the field samples collected)? • Were the recommended sample storage and transport procedures followed pri o r to analysis? • If used, were direct reading instruments properly calibrated? What error rate can be expected from the instrument measurements? • How was the number of samples that were taken determined? • If applicable, were individual workers and shifts randomly selected for sampling using appropriat e methods? • Were the samples properly collected to assess intended exposures (i.e., average or worst-case exposures)? E . Sampling Resu l ts and Discussion :Provide a summary ofthe results ofthe monitoring study. Include units , sampling time intervals , and limits of detection where applicable. Pr ovide any necessary con text or evaluatio n ofthe results. • Describe any equations or calcul ations u sed to evaluate the results , including exposure as sessment calculations, statistical calculations, or mathematical exposure modeling done using the data collected. • Characte rize the results in terms ofthe population targeted in the monitoring study (i.e., individual SEGs, et c.). • Discuss the uncertainties in the results. • Compar e the results to previous monitoring studies. F . Description ofIndustrial Hygiene Program: Briefly describe the industrial hygiene program at the facility where the monitoring study was conducted. • Is a written industrial hygiene program in place? What are the basic elements ofthe program? • What types ofcontrols (i.e., ventilation, work practices, respirators) are in place to prevent inhalation exposure, as well as other types of exposur e? • What types ofemployee training are conducted to inform workers ofthe hazards related to their jobs? • What types ofeva luation methods are used to assess the effectiveness ofthe program? How frequently is monitoring conducted? How oft en is the program evaluated? If you h ave any questions r egarding this guidance, please contact the OPPTIEETD/CEB engineer responsible for your case or Jenni fer Sahmel, CEB Industrial Hygienist, at (202) 564-8524 or sahmel. j ennifer@ epa.gov .References Hewett, Paul. Past C hair , Exposure Assessment Strategies Committee , American Industria! Hygiene As so ciation. Unpublished/Verbal communication: General Guidance on Dev e lopin g an Exposure

A ss e s sment Strategy. April2002. Mulhausen, John R. and Damiano, Joseph. A Strategy for Assessing and Managing Occupational Exposures, Second Edit i on. Fairfax, VA: American Industrial Hygiene Association Press, 1998. National Institute of Occupational Safety and Health. Occupational Exposure Sampling Strategy Manual, Chapter 3: Exposure Measurement Sampling Strategy . pp. 34-35 . DHHS (NIOS H) Publication No. 77-173 , January 1977. http: // www.cdc.gov / niosh/77-173.html Plog , Barbara, ed. Fundamentals oflndustrial Hygiene. T hird Edition: Chapter 17, Methods o f E valuat i on, pp. 397-416. National Safety Council, 1988. · U.S. Envi ronm ental Protection Agency, Technical Document for Characterizing and Presenting Sum mary Chemical Exposure Assessment Result s (working draft), pres ented at the Voluntary Children' s Chem ical Evaluation Program Workshop, December 11-13,2001. http: // www .epa. gov I chemrtk/ etechdoc. pdf. 1 Mulhausen, John R. and Damiano, Joseph. A Strategy for Assessing and Managing Occupational Exposures, 2nd edition. American Indu stria l Hygiene Association (AIHA Press): 1998, pp . 41-56 . 2Mulhausen, John R. and Damiano, Joseph. A Strategy for Assessing and Managing Occupational Exposures, 2nd edition. American Industrial Hygiene Association (AIHA Press): 1998 , pp. 89 -112. 3Mulhausen , John R. and Damiano, Joseph. A Str a tegy for Assessing and Managing Occupational Exposures, 2llil edition . American Industrial Hygiene Association (AIHA Pre ss): 1998 , pp. 10 7. 4Nationall nstitute of Occupational Safety and Health. Occupational Exposure Sampling Strategy Manual, Chapter 3: Exposure Measurement Samp ling Strategy. pp. 34-35. D HHS (NIOSH) Publication No. 77-173 , January 1977. http:/ / www.cdc.gov / niosh/77-173.html 5National Institute of Occupational" Safety and Health. Occupational Exposure Sampling Strategy Manual , Chapter 3 : Exposure Measurement Sampling Strategy. pp. 35. DHHS (NIOSH ) Publication No. 77 - 1 73 , January 1977. http: //www . c dc.go v / niosh/77-l7 3 .html 6Mulhausen , John R. and Damiano , Joseph. A Strategy for Assess in g and Managing Occupational Exposures, 2nd edition. American Ind ustrial H ygiene Association (AIHA Pre ss): 1998 , pp. 10 6- 110.