NYC-WTC_000209193

NYC 9/11 Public Portal Document

Inorganic Acids OSHA has taken approximately 45 samples for inorganic acids such as hydrochloric, phosphoric, and sulfuric acids. One sample for sulfuric acid was found to exceed OSHA’s permissible exposure limit (PEL) of 1 mg/ml Additional sampling results are pending.

Oxides of Nitrogen/ Sulfur: Sampling on grappler operators on the rubble pile, and on ernployees at the truck wash stations revealed trace levels of nitric oxide and nitrogen dioxide. This was repeated (1) sample, now that the wash station is been enclosed. SOj personal and area results were found to be below OSHA limits.

Metals: OSHA has taken 784 samples (excluding bulk and blank samples) to monitor worker exposures to dusts, fumes, oxides, and other compounds of metals such as antimony, beryllium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, vanadium, zinc, cadmium, magnesium, and arsenic. 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 instances of overexposures as follows; copper (12); iron oxide (23); lead (12); and cadmium (2). Accordingly, OSHA is recommending that workers engaged in these operations wear appropriate respiratory protection.

Mercury OSHA has taken 155 air samples for inorganic mercury. Results for 82 of those air samples have been received and no mercury was detected. Also, 36 bulk samples previously collected from rubble were re-analyzed for mercury. None was detected.

Ionizing Radiation; A survey of the rubble pile was conducted on 10/22-10/23 to check for latent radiation with particular attention to alpha radiation. Preliminary results show no elevated levels.

Dioxins: OSHA has taken 15 dioxin samples in the plume over hot spots in (and around the perimeter of) the rubble pile. Dioxin levels detected around the perimeter are lower than those found directly over the pile. To date, only one sample taken on the rubble pile showed dioxin levels which exceeded background levels. Dioxins are considered collectively as suspect human carcinogens. OSHA does not have a PEL for 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 eight samples which reached or exceeded OSHA’s coal tar pitch volatile PEL of 0.2mg/m’. These personal samples were taken on the pile on iron workers and grappler operators. OSHA continues to strongly recommend the use of respiratory protection when working on the rubble pile. Freon R-22, Hydrogen Fluoride & Phosgene: OSHA has taken 137 samples for Freon R-22 (chlorodiflouromethane). The majority of sample results received to date show no detectable airborne levels. During operations involving Freon removal from the auxiliary chiller, direct reading instruments used by the entrants revealed readings ranging from 100 ppm to 500 ppm. SCBA ‘s 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 REL for Freon is lOOOppm..) Sampling for decomposition products of Freon R-22 for hydrofluoric acid (HF) and phosgene to date showed no detectable levels.

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NYC-WTC_000209194