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Misuse of Exposure Reporting in Acute Risk Assessment

Misuse of Exposure Reporting in Acute Risk Assessment. John S. Morawetz International Chemical Workers Union Council/UFCW Center for Worker Health & Safety Training Cincinnati, Ohio (513) 621-8882 JMorawetz@ICWUC.org. Acute Exposure Guideline Levels.

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Misuse of Exposure Reporting in Acute Risk Assessment

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  1. Misuse of Exposure Reporting in Acute Risk Assessment John S. Morawetz International Chemical Workers Union Council/UFCW Center for Worker Health & Safety Training Cincinnati, Ohio (513) 621-8882 JMorawetz@ICWUC.org

  2. Acute Exposure Guideline Levels Since 1996 the EPA has convened meetings of a National Advisory Committee for Acute Exposure Guideline Levels (AEGLs) Committee of Toxicology of the National Research Council and National Academy of Sciences “Once in a lifetime short term exposures” for general public

  3. Health Outcomes • AEGL-1 Notable discomfort • AEGL-2 Irreversible or serious, long lasting effects including impaired ability to escape • AEGL-3 Death or life threatening

  4. Time Periods • Levels are set for 5 time periods: • 10 and 30 minutes, 1, 4 and 8 hours for each health outcome • Total of 15 levels per chemical

  5. Application • General population including infants, children, asthmatics and other susceptible groups • Unlike occupational recommendations, intended for once in a lifetime exposure

  6. Caveats Primary - Control Exposures; hierarchy of controls Substitution Pollution Prevention Need Multi disciplinary efforts Toxicologists, Physicians, Epidemiologists, Industrial Hygienists, Statisticians, Engineers

  7. Caveats • “Intended to be used as planning tools” • “when an actual chemical emergency occurs, there often is no time to measure airborne concentrations” • “Not to be used as safe limits for routine operations or definitive delineators between safe and unsafe exposure conditions” (AIHA, ERPG handbook, 2000)

  8. AEGL Committee’s misuse of human studies • Inaccurate reporting in draft report • Time period of sample • Area vs. personal vs. bulk • TWA vs. instantaneous • Anecdotal vs. case or full study • Rejection of reconstruction studies • Inappropriate use of range of data

  9. Inaccurate Reporting • Inaccurate summary of level • “No exposure measurements” SOP • Incorrect range reported - phosphine • Time period associated with measurement • “No exposure time noted” phosphine (Wilson) • Range of levels with no time period • trichloroethane – fatality reconstruction • methanol – NIOSH HHE

  10. Inaccurate Reporting • Area vs. personal samples • Propylene Glycol Dinitrate • Hydrogen Cyanide (Leeser) • Reported only "routine" instantaneous samples (1 to 3 ppm) rather than available personal samples

  11. Inaccurate Reporting • Area vs. personal samples • Methanol • AEGL stated "measured in the vicinity of the duplicators". • NIOSH HHE (1981) states "Breathing zone samples were collected for methyl alcohol vapors over a 25 minute sampling period".

  12. Inaccurate Reporting Bulk vs. Area vs. Personal samples • “raw acetylene contained less than 3 ppm “ Used as a personal exposure – phosphine Case reports described as anecdotal - phosphorous trichloride - trichlorethylene

  13. Rejection of fatality reconstruction studies • Simulation of task with sampling • Phosphine (Hager) • Trichloroethane

  14. Inappropriate use of range of data • Attributed to which exposure level? AEGL - Single Upper limit of range Examples: Propylene Glycol Dinitrate • Maximum value of 400 inst. Samples Hydrogen Cyanide • 34 samples in 8 job titles

  15. Hydrogen Cyanide Exposures by Job TitleLeeser, 1990

  16. Summary • Multi disciplinary Risk Assessment committees • Draft reports • Committee discussion and recommendation • Final approval • Accurate summary of original articles • Uranium Hexafluoride

  17. Composition of CommitteePreponderance of one expertise Bias towards one expertise

  18. Current Issues • Hydrogen Cyanide • Leeser: used as primary study • Grabois study, 1954 • Industrial Hygiene survey with NO health survey • Occupational Application of AEGLs • Emergency Response

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