NYC-WTC_000229688

NYC 9/11 Public Portal Document 1-ZA —; 1 z : ; Nve uaw uepar tnieni. urni I r\i i.

Industrial Hygiene Sun^ Federal Bureau of Investigation, Staten Island, NY

4.0 Exposure Criteria

The US Department of Labor Occupational Health and Safety Administration (OSHA) regulates exposure to air contaminants. The OSHA permissible exposure limits represent legal standards. Most of the limits are time-weighted averages over an eight-hour shift These are intended to prevent long term or chronic health effects to workers exposed over eight-hour days for five days a week over a working lifetime. These limits are called an eight-hour time weighted average (8 hr TWA). Aiife

Most workers, but not all, will be protected from adverse health effects if their exposures are maintained below the OSHA regulatory levels. A small percentage may experience adverse health effects because of individual susceptibility, or a pre-existing medical condition. In addition, some hazardous substances may act in combination with other workplace exposures, the general environment, or with medications or personal habits of the worker to produce adverse health effects, even if the occupational exposures are controlled at the level set by OSHA. I Asbestos The World Trade Center tower buildings 1 and 2 had asbestos containing fire proofing on the structural steel on some of the floors. This consisted primarily of chrysotile asbestos. Asbestos fibers are recognized as a human carcinogen, which primarily affect the respiratory system. The types of cancer associated with asbestos exposure include lung cancer, pleural mesothelioma and peritoneal mesothelioma. Asbestos can also cause asbestosis, a debilitating respiratory disease. The latency period between exposure to asbestos and development of disease is 15 to 25 years. The principle route of exposure to asbestos is through inhalation. The Occupational Safety and Health Administration (OSHA) regulates asbestos under the construction standard (cited as 29 Code of Federal Regulations Part 1926.1101). The permissible exposure limit for asbestos is 0.1 fibers per cubic centimeter of air (f/cc) as an eight-hour time weighted average. There is also an excursion limit of 1.0 fZee over a 30-minute sample.

Asbestos bulk samples were also taken at the landfill. Sample results are reported as either none detected, or the specific type of asbestos material is identified, and where possible the quantity of the asbestos is indicated. The OSHA asbestos standard as well as the asbestos standards defines asbestos containing material as having greater than !*■ % asbestos.

Metals Given the extent of pulverization of the building there is a small potential for exposure to heavy metals present in the dust. OSHA regulates exposure to a number of metals as an S-hour TWA. The OSHA PELs for the scanned metals are: Silver 0.01 mgZM3 Aluminum 15 mgZMS Arsenic 0.01 mg/M3 Antimony 0.5mg/M3 Barium O.Smg/M3 Beiyllium 0.002 mg/M3 Cadmium O.OOS me/M3

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NYC-WTC_000229696