VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

Table 1. Inhalation health risk screening benchmarks used in this assessment.

Agency | Screening Benchmark

1. Short-Term Exposures OSHA Permissible Exposure The maximum allowable exposure to a concentration of Limit (PEL) a substance in the air. PELs are set to protect workers and are based upon an 8-hr time-weighted average exposure. PELs are enforceable standards. OSHA Short Term Exposure A 15-minute time-weighted average that should not be Limit (STEL) exceeded at any time during a workday. STELs are enforceable standards. ATSDR Acute inhalation An acute MRL protects against exposures that may last Minimal Risk Level 1-14 days. An MRL is defined as an amount of (MRL) chemical that gets into the body (i.e., dose) below which health effects are not expected. ATSDR Intermediate inhalation An intermediate MRL protects against exposures that Minimal Risk Level may last 15 - 364 days. (MRL) EPA- Provisional Subchronic The STSC subchronic RfC is the exposure level that is STSC Reference likely to protect humans from adverse health effects Concentration (RfC) when exposed over a period not exceeding 10% of their lifetime (usually assumed to be 7 years). These values are only provisional guidance. ACGIH Threshold limit value A recommended exposure limit based on an 8-hour (TLV) workday and a 40-hour work week. NIOSH Recommended The maximum recommended exposure limit determined Exposure Level (REL) to protect workers. EPA Asbestos Hazard This standard was developed to be applied to asbestos in Emergency Response schools. School children were not to be allowed back Act (AHERA) level of into an “abatement” area (an area where activities were concern undertaken to reduce air concentrations) until several consecutive readings were less than the AHERA standard.

DRAFT-DO NOT QUOTE OR CITE 17 October 2002

NYC-WTC_000149098