NYC-WTC_000232887

NYC 9/11 Public Portal Document

Mercury OSHA has taken 207 air samples for inorganic mercury. Results for 182 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 and none was detected. Additionally, 10 bulks were taken on 1/3, with one (1) sample detecting mercury at 0.9ppm and nine (9) samples being non-detected. 38 bulk samples were taken between 1/8 and 1/11/02; partial results indicate 0.1 to 0.2 ppm mostly in around the footprint of Bldg.-6, with more results pending.

Ionizing Radiation: A survey of the rubble pile was conducted on 10/22-10/23 to check for latent radiation witli particular attention to alpha radiation. Results show no elevated levels of concern from either known building latent radiation sources or any terrorist origin source materials.

Dioxins: OSHA has taken 10 dioxin samples (excluding blanks) 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. Dioxms aie considered collectively as suspect human carcinogens. OSHA does not have a PEL for dioxins. Polynuclear Aromatic Hydrocarbons OSHA has taken 110 samples (excluding blanks). 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 a total of 198 samples for Freon R-22 (chlorodiflouromethane), hydrogen fluoride, and phosgene. Only one Freon sample resulted in a detectable level of 6.4 ppm

during the transfer of Freon from the auxiliary chiller, and all other samples were none-detected. OSllA does not have an exposure limit for Freon R-22. (The NIOSH REL for Freon is lOOOppm..) Sampling for the decomposition products of Freon R-22, hydrofluoric acid (HF) and phosgene showed no detectable levels.

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