OSHA exposure summary, WTC rubble pile, Feb 2002

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 apparent overexposures to silica occurred were in the rubble pile/pit; an area where OSHA continues to encourage the use of respiratory protection. Organic Compounds: OSHA has taken a total of 636 samples (excluding bulk and blank samples) for organic compounds such as acetaldehyde, acrolein, acnloniirile, benzene, 2-butanone, carbofurans, dioxin, PCBs, ethylbenzene, formaldehyde. Freon R-22 (chlorodiflouromethane), hexone, isocyanates (e.g. MDI, TDI), perchloroethylene, polynuclear aromatics, phosgene, stxrene, toluene, 1-3 butadiene, trichloroethylene, tiny] 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 beloxs- OSH.A limits. However, one personal sample result for a benzene sample taken was found to be at the S-hr. OSH.\ Allowable Limit concentration of I ppm. This was found on a backh.oe operator moving debris on 10/7/01. See information below for the specific counts in regards to polynuclear aromatics. Freon R-22, phosgene and dio.xin.

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 ox'er 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 Hjdrocarbons OSHA has taken 110 samples (excluding blanks). The majority of the samples have not shown the presence of benzof ajpxrene and 'or one or more of five additional fused polycyclic hydrocarbons: anthracene, acridine, pyrene, chrysene and phenanthrene. Sample results to date ha'.'e 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 202 samples for Freon R-22 (chlorodiflouromethane), hydrogen fluoride, and phosgene. Only one Freon sample resulted in a delectable le'. el of 6.4 ppm during the transfer of Freon from the auxiliaiy chiller, and all other samples '.'. ere

Page 2 of 3

CITY_21MC100_003144965 NYC-WTC_000186426