NYC-WTC_000176130

NYC 9/11 Public Portal Document [[Nancy Jefje^^^Re: Nextcbnference~c^aH forthe~indo6rTaskforce COC/Behchmarks Comr^ttee Page 2'I

a. WTC Building Materials Criteria: COC's selected for this group include pulverized building materials that were released in large quantities over a large area from the collapse of WTC. To address the concern of irritation, chemicals with known potential to cause irritation should be included as a COC. However, of all the possible building materials, only those found consistently in dust and air should be included. These could be pH, fibrous glass, asbestos (not an irritant), etc. These materials may be the predominant players in the "how clean is clean" assessment. Criteria could focus on degree of known irritancy/other health effects and degree of prevalence.

b. Fire Related Chemicals: COC's selected for this group would be those chemicals released from the fire that have irritancy/other health effects that were present at levels in air of potential concern and that accumulated in dust over time. The EPA air dataset would be used to determine if the chemicals were at potential levels of concern (to the maximum extent possible). One approach would be develop or choose an existing level of concern in air for a chemical and use existing air data to define an area that was impacted at this air level. If the area does not extend beyond ground-zero (or any area we define) exclude the chemical from the list of COC's. Another approach would be to use exposure/risk assessment techniques to define a level of concern of the chemical in dust (keep in mind the uncertainty here). Then use a simple but conservative air deposition model to back-calculate the air concentration of the chemical that would result in this dust concentration. This air concentration would then be used to define an area of impact using the EPA dataset. If the area does not extend beyond ground-zero (or other area) drop the chemical from the list.

This approach is a suggested approach for discussion.

Forwarded by Robert L. Chinery/DEHA/CEH/OPH/DOH on 03/15/02 02:26 PM

Robert L. Chinery To: Maddaloni.Mark @ epamail.epa.gov 03/12/02 01:45 PM cc: [email protected], [email protected] Subject: Re: Next conference call for the indoor Taskforce COC/Benchmarks Committee(Document link: Robert L. Chinery)

Hi Mark,

I wanted to discuss with you some thoughts and data related to the choice of materials that may be specific markers for WTC dust. I think the data is indicating that fiberglass may be the best and least equivocal material that is an indicator of the presence of WTC demolition related dust. The following findings appear to indicate this.

NYC-WTC_000176131