NYC-WTC_000204863

NYC 9/11 Public Portal Document 11/09/01 FRI 16;47 FA.X .518 402 7819 NYSDOH-BTSA IfejiJOo

Public Health Implications

Although the highest levels of VOCs were found in samples from the plume at the WTC debris pile, these results are not likely to represent the potential exposure of the residents. Residents are unlikely to be in the plume at the debris pile where they could be exposed to these levels for any' length of time. Therefore, the sampling results for areas potentially affected by the plume (i.e., at downwind locations) but not at the debris pile arc more relevant for evaluating potential exposure to the residents. The levels of some of the chemicals in tire plume mca.surcd at the debris are elevated and exceed typical background ranges, and recovery and emergency workers should take precautions to limit their exposure to emissions from the plume.

The levels of VOCs at the upwind sites (75 Park Place and 225 Rector) arc generally within the range of typical background levels.

The air concentrations of VOCs at the downwind site (140 Broadway) were generally greater than those measured upwind (75 Park Place and 225 Rector) and tj'pical background concentrations. However, none of the WTC-related chemicals measured at 140 Broadway exceed both typical background levels and air compari.son values except benzene, chloromethane and styrene.

None of the chemicals detected above background at 140 Broadway exceed intermediate or short-term air comparison values except benzene. The average and highest levels of benzene at 140 Broadway are slightly' above typical background and are near the intermediate comparison value for this chemical. This comparison value for benzene is about 90 times lower than the exposure level that caused mild neiirological effects in mice exposed regularly for 30 days.

The benzene air concentrations at 140 Broadway (as v.'cll as typical background concentrations of benzene) exceed the health comparison value for benzene in air, based on carcinogenic effects following long-tenn exposure. The cancer comparison value is the air concentration associated with an increased hfetune cancer risk of onc-in-one million (10-6). Because the estimated duration of exposure is at most one year, and because elevated levels are unlikely to persist for extended periods of lime (c.g. the fires will be put out and tire wind duection will periodically change), eomro.unity exposures are not expected to result in cancer risks that are appreciably increased over those resulting from background e.xposure. These estimated cancer risks do not exceed onc-in-ten thousand (10-4), above which actions are usually taken to reduce exposure.

The average levels of cldoromethane and styrene also exceed background and their air comparison values based on cancer effects and long-term exposure. Again, based on the low potential for long-term exposure to elevated levels, this is not expected to result in an appreciable increased cancer risk, but one similar to the risks resulting from exposure to background levels.

Limitations of Health Assessment

The primary limitation of this assessment is that the list of VOCs measured may not be completely representative of the emi-tsions from the fires and recovery activities at the World Trade Center site. The analytical methods did not include all of the numerous combustion products that can be gimcratcd from the fires, which, in addition to tlie measured VOCs, could afreet air quality and public health. Soras chemicals that are icnowu to be produced by fires (e.g. aldehydes, acrolein) and that are strong respiratory irritants were not measured.

When odors are present, it is not lunisual for some people to experience short-term effects such as respiratory' irritation and effects such as headaches and dizziness. These effects tend to diminish once exposure to the odors is stopped, and usually do not result in long-term health consequences. Some people are more likely to experience these effects than others.

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