OSHA exposure summary, WTC rubble pile, Feb 2002

NYC 9/11 Public Portal Document

none-detected. OSH.A does not have an exposure limit for Freon R-22. (The NIOSH REL for Freon is 1 OOOppm..) Sampling for the decomposition products of Freon R-22, hydrofluoric acid (HF ) an-.i phosgene showed no detectable levels.

Inorganic Acids OSHA has taken approximately 111 samples for inorganic acids such as hydrochloric, phosphoric, and sulfuric acids. Two samples for sulfuric acid were found to exceed OSHA’s permissible e.xposure limit (PEL) of 1 mg'mh O.xides of .Xitrogen/ Sulfur; Sampling on erappler operators on the rubble pile, and on employees at the truck wash stations revealed trace levels of nitric oxide and nitrogen dioxide. SO. personal and area results were found to be below OSHA limits.

Metals: C'SHA has taken a total of 1051 samples (excluding bulk and blank samples) to monitor worker exposures to dusts, fumes, oxides, and other compounds of metals such as antimony, beiydlium, chromium, cobalt, copper, iron, lead, manganese, mercury', 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 o\'erexposures as follows: copper (13): iron oxide (26); lead (14); and cadmium (2). Accordingly, OSH.A is recommending that workers engaged in these operations wear appropriate respiratory' protection. See infonnation below for the specific counts in

regards to mercury.

Mercury OSHA has taken 224 air samples for inorganic mercury. Results for 224 of those air samples have been received and no mercury was detected. Also. 36 bulk samples previously collected from rubble were re-analy'zed 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 w ere taken between 1/S and 1/11/02; results indicate 0.1 to 0.2 ppm mostly in around the footprint of Bldg.- 6, and in the pit between WTC tower 1&2.

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

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