NYC 9/11 Public Portal Document
Metals: OSHA has taken 626 air samples to monitor worker exposures to dusts, fumes, oxides, and
other compoimds of metals such as antimony, beryllium, chromium, cobalt, copper, iron, lead,
manganese, molybdenum, nickel, vanadium, zinc, cadmium, magnesium, arsenic, and
mercury. 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 (9); iron oxide (20); lead (12); and cadmium (2).
Accordingly, OSHA is recommending that workers engaged in these operations wear
appropriate respiratory protection.
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 samples for dioxin and these samples were analyzed by EPA. One initial
sample, representing exposure directly on the pile, showed elevated levels of dioxins when
compared to ambient background levels. This value was comparable to the levels found by
EPA sampling. The dioxins at this location are being emitted from the on-going rubble fire.
Additional sampling was conducted around the perimeter of the pile and revealed levels that
were considerably lower than those on the rubble pile. Dioxins are considered collectively as
suspect human carcinogens. OSHA does not have a worker standard for dioxins. OSHA is
coordinating with EPA, and the Salt Lake City Analytical Laboratory to fully assess the risk
posed by the elevated levels of 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 seven 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 105 samples for Freon R-22 (chlorodiflouromethane). The majority of sample
results received to December 17*’’ reveal non-detectable airborne levels. During operations
involving Freon removal from the auxiliary chiller that started on 12/5/01, direct reading
instnunent revealed readings ranging from 100 ppm to one peak near a leaky valve of 500
ppm. SCBA tanks 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..) In
response to information about exposure to the decomposition by-products of Freon R-22 used
in the air conditioning systems of WTC towers, sampling for hydrofluoric acid (HF) had been
conducted. Results for HF revealed non-detectable levels. Sample results for phosgene to
date show non-detectable levels.
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