Letter re: EPA/DEP WTC dust cleanup at 114 Liberty Street,

NYC 9/11 Public Portal Document

15

by the WTC collapse, then EPA should address these problems through either the CERCLA or other statutes.

As discussed in my 7/4/03 report,^' the EPA background study itself of midtown Manhattan is invalid for several reasons. First, the buildings were not selected at random. EPA staff actually knocked on doors of their own choosing to solicit participation in the study, and EPA has a history of biasing of data Second, the data itself has no statistical significance - there is too high a variability to permit any conclusions about actual background levels in midtown Manhattan.

EPA Misrepresentation of silica health effects - a carcinogen EPA has been misrepresenting the health effects of silica in its documents related to the World Trade Center. EPA has carefully avoided any reference to the fact that it is a known human carcinogen and is linked to some auto-immune diseases, as well as causing silicosis and chronic bronchitis.

EPA’s statements about silica are given below, followed by the evaluations of the health effects of silica by NIOSH and the National Toxicology Program (NTP):

EPA’s statements about the health effects of silica after the WTC disaster

The only information that EPA provided on the health effects of silica in WTC-related documents is in its Contaminants of Potential Concern.^ In this document, EPA acknowledges that asbestos and other WTC contaminants will cause cancer, but EPA says nothing whatsoever about lung cancer from silica. EPA only mentions that silica will cause “point of contact toxicity” in the lung: Target organs and critical effects resulting from ingestion and dermal exposures generally differ across individual COPC, though lead, dioxins, and PAHs are all considered potential human carcinogens via the ingestion route. Each of these contaminants can affect a wide range of biological systems, but each generally exerts its effects via different mechanisms.

At high concentrations, inhalation exposure to several of the COPC (asbestos, PAHs, fibrous glass, and crystalline silica), as well as the small particulate matter released during the WTC disaster, has been shown to result in point of contact toxicity to the lung. Specific lung effects vary across these substances, ranging from acute irritant effects produced by fibrous glass to cancers of the lung associated with asbestos.

Furthermore, EPA’s October, 2002 draft risk assessment for the WTC disaster is totally silent about the health effects of silica.^ In marked contrast, this same October, 2002 draft risk assessment provides considerable detail on the carcinogenicity of other WTC toxic constituents, such as asbestos. From this absence of any health information on silica, the reader is given the distinct impression that crystalline silica is neither a carcinogen nor a substance that will cause other long term permanent health effects.

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