NYC-WTC_000199946

NYC 9/11 Public Portal Document

Oxides of .Nitrogen/ Sulfur: Sampling on grappier operators on the rubble pile, and on employee.s mnning track w'ash stations revealed trace levels of nitric oxide and nitrogen dioxide. iOy personal and area results were found to be below OSHA limits.

Metals: OSHA has taken 653 air samples to monitor worker exposures to dusts, frmes, oxides, and other compounds of metals such as antimony, beiwllium. chromium, ctbalt, copper, iron, lead, manganese, molybdenum, nickel, vanadium, zinc, cadmium, magnesium, arsenic, and mercury. Results from these samples are generally well below the applicable OSHA limits. However, torch cutting and burning structural steel at the rubble pile have resulted in instance,s of overexposures as follows: copptr (10); iron oxide (21); lead (12); and cadmium (2). Accordingly, OSHA is recommending that w'orkers engaged in these operations wear appropnate respiratory proteciicn.

Ionizing Radiation: A surveyor the nibble pile was conducted on 10/22-10/23 to check for latent radiation with particular attention to alpha radiation. Preliminary results showno elevated levels.

Dioxins: OSHA has taken samples for dioxin and these samples were analyzed bvEPA. One initial sample, representing exposure directly on the pile, showed elevated levels of dio.xins when compared to ambient background levels. This value was comparable to the levels found by EPA sampling. The dioxins at this location are being emitted from the on-aoing rubble fire. Additional sampling was conducted around the penmeter of the pile and revealed levels that were considerably lower than those on the rubble pile. Dioxins are considered collectively a.s suspect human carcinogens. OSHA does not have a worker standard for dioxins. OSHA is coordinating with EPA, and the Salt Lake City Analytical Laboratory to fully assess the nsk posed by the elevated levels of dioxins, Polynuclear Aromatic Hydrocarbons OSHA has taken 132 samples. The majority of the samples have not shown the presence of benzo(a)pyrene and/or one or more of five additional fused polycyclic hydrocarbons: anthracene, acridine, pyrene, chrysene and phenanthrene. Sample results to date have identified seven samples which reached or exceeded OSHA’scoal tar pitch volatile PEL of 0.2mg./W . These personal samples were taken on the pile on ironworkers and grappier operators. OS FIA continues to strongly recommend the use of respiratory protection when working on the rubble pile. Freon R-22, Hydrogen Fluoride & Phosgene; OSHA has taken 105 samples for Freon R-22 (chlorodiflouromethane). The majority of sample results received to December 17* reveal non-detectable airborne levels. During operations involving Freon removal from the auxiliary chiller that started on 12/5/01, direct reading instrument revealed readings ranging from 100 ppm to one peak near a leaky valve of 500 ppm. SCB A tanks were and are being worn by workers, and masks are to be worn only when direct reading instruments reveal 850 ppm Freon and or less than 20.4% Oxygen. OSHA does not have an exposure limit for Freon R-22. (The NIOSH R,EL for Freon is lOOOppm..) In response to information about e.xposure to the decomposition by-products of Freon R-22 used in the air conditioning systems ofWTC towers, sampling for hydrofluoric acid (HF) had been conducted. Results for HF revealed non-detectable levels. Sample results for phosgene to date show non- detectable levels.

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NYC-WTC_000199947