WTC health criteria appendix, Dec 2001

NYC 9/11 Public Portal Document

methodology which uses transmission electron microscopy (TEM), and because of its basis in "background" (vs a risk basis) includes all asbestos fibers greater than 0.5 microns in length. Worker values are based on phase contrast microscopy (PCM, - which doesn’t distinguish asbestos from other fibers) or, for results above the PCM screening value, TEM to derive a PCM equivalence that includes all asbestos fibers greater than 5 microns in length.

4. Screening values for chromium were based on the most toxic form (hexavalent)

5. EPA - Hazard Evaluation Handbook (HEH) (carcinogen) > 1 year of continuous exposure equating to an excess lifetime cancer risk of one-in ten thousand

6. EPA - HEH (noncarcinogen) > Hazard Quotient (HQ) = 10

7. National Ambient Air Quality Standard (NAAQS) - Lead is a 3 month average - PM2 5 is a 24 hour average - Sulfur Dioxide is a 24 hour average primary standard

8. Air Quality Index (AQI)

9. Non cancer effects based on CAL-EPA toxicity studies

10. American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV)

11. Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation minimum risk level (MRL) X 10

12. ATSDR acute MRL

13. Lower Explosive Limit (2 - 11 %)

14. National Institute of Occupational Safety and Health (NIOSH)

15. Proposed Reference Concentration (RfC) - HEH (noncancer) > Hazard Quotient (HQ) = 10

16. Based on Benzo(a)pyrene toxicity equivalency factor toxicity equivalency factor (TEF)

17. EPA National Center for Environmental Assessment (NCEA) provisional inhalation Slope Factor (3.1 E 00 mg/kg/day'')

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CONFIDENTIAL, CITY_2IMCl00_003423732 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

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