NYC-WTC_000199943

NYC 9/11 Public Portal Document

drilling the concrete slurry wall, 6) flagging operations in pit, and 7) while chipping concrete with power tools during demolition activities at 7 WTC’s parking garage. Most of the work areas where appu'-ent overexposures to silica occutred were in the rubble pile/pit; an area where OSHA continues to encourage the use of re,spiratory protection. Organic Compounds; OSHA has taken a total of 636 samples (excluding bulk and blank samples) for organic compounds such as acetaldehyde, acrolein, acrylonitrile, benzene, 2-bufanone, carbofurans, dioxin, PCBs, ethyl benzene, formaldehyde, Freon R-22 (chlorodiflouromethane), hexone, isocyanates (e.g. MDl, TDI), perchloroethylene, polynuclear aromatics, phosgene, styrene, toluene, 1-3 butadiene, trichloroethylene, vinyl chloride, glutaraldehyde, and xylene. Screening samples initially showed elevated levels of some organic chemicals resulting from the fires burning in the rubble pile. Subsequent personal and area samples show worker exposure levels to be below OSHA limits. However, one personal sample result for a benzene sample taken was found to be at the S-hr. OSHA Allowable Limit concentration of 1 ppm. This was found on a backhoe operator moving debris on 10/7/01. See information below for the specific counts in regards to polynuclear aromatics, Freon R-22, phosgene and dioxin.

Dioxins: OSHA has taken 10 dioxin samples (e.xcluding 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 tho.se found directly over the pile. To date, only one sample taken on the rubble pile showed dioxin lev'els which exceeded background levels, Dioxins are considered collectively as suspect human carcinogens. OSHA doe,s 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 )p\Tene and/or one or more of fire additional fused polycyclic hydrocarbons: anthracene, acridine, pyrene, chrysene and phenanthrene. Sample results to date har-e identified eight samples which reached or exceeded OSHA's coal tar pitch volatile PEL of 0.2mg/ni’. 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 202 samples for Freon R-22 (chlorodiflouromethane). hydrogen fluoride, and phosgene. Only one Freon sample resulted in a detectable lerel of 6.4 ppm during the transfer of Freon from the auxiliarx' chiller, and all other samples were

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