EPA memo re: wipe sampling and cancer risk at WTC,

NYC 9/11 Public Portal Document

ESTIMATING INCREASED HEALTH RISKS FROM VARIOUS WTC EXPOSURE SCENARIOS

The following represents my efforts as a staff scientist to characterize any elevated health risks from exposures to WTC asbestos-contaminated dusts. As stated at the beginning of this memorandum, this risk assessment does not represent any official EPA analy'^is or position and does not necessarily reflect EPA po’icy. It has not been reviewed by EPA, i here are many altetnate ways to perform a risk assessment other than the one presented below. This risk assessment has a wide range of uncertainty both because of th. limited data and the many assumptions that were utilized.

The EPA does not consider any exposure to a man-made carcinogen to be acceptable, but does base its actions in existing exposure situations according to the degree of elevated risk. The EPA chooses a degree of protection, or risk level, as a criteria for abating exposures.

The EPA generally considers an upper-bound lifetime cancer risk to an individual of between 10*^ audio** as a safe range. A risk of 1represents a probability that there may be one extra cancer case in a population of 10,000 (1 per 10,000). A 10** risk is the probability that there may be one extra cancer case in a population of one million people over a lifetime of exposure (1 per 1,000,000. The National Contingency Plan (NCP) (Superfund) requires that the 10* risk level should be the point of departure; the goal in any response by the EPA to ameliorate exposures to carcinogens from man-made sources. A response action is generally warranted if the cumulative excess carcinogenic risk for any single individual affected by a site exposing humans to carcinogens exceeds 1 in 10,000 (the 10* risk level) using reasonable maximum exposure assumptions for either the current or reasonably anticipated future exposures.

Scenario 1 - Volunteer at Ground Zero for two weeks

A person volunteered to provide refreshments to the rescue workers on the perimeter of Ground Zero for two weeks. The volunteer spent 12-hour days, going home to Brooklyn at night S/he stayed outdoors for the majority^of the time, but came inside to one of the adjacent evacuated hotels for shelter from the elements, to rest, and eat. Approximately 3 hours per day were spent inside this building.

This person also lived/may live in an urban environment for a life of 85 years, with and exposure level of 6 X 1 O'* (0.000006) s/mL.*’

From Table 2, the asbestos level inside the contaminated building near Ground Zero is estimated to be 10 s/mL, midway between die “passive” conditions tested in the high-exposure building near Ground Zero, and the level estimated for cleaning out a storage room.

The level at the refreshment stand on the perimeter of Ground Zero is estimated to be 0.16 s/mL, towards the high side of EPA’s air readings outdoors near Ground Zero in the month of October, but low for the month of September,. (Internet yersion)

- 11 -

NYC-WTC_000140269