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

NYC 9/11 Public Portal Document

How to use Table 3

First, look for the health effect that will occur at the lowest levels of asbestos. This would be mesothelioma, a type of cancer that affects the cavity, of the thorax, and also lung cancer if you are also a smoker. If a person inhales the equivalent of 0.00031 fibers of asbestos/milliliter of air for one year, then their increased risk of getting mesothelioma is 1 in a million. If they breathe 10 times that much for one year (0.0031 f-yr/mL), then the chance is increased to 1 in 100,000. Then, go over to the right hand columns which gi/e a range of different time periods. Say you are interested in those exposures which will increase mesothelioma cancer risks by 1 in 10,000. A person would need to breath the oilowing concentrations of asbestos for the following time periods to increase the risk by 1 in 10,000:

Total dose required to increase risk of mesotheltoma by 1 in 10,000 fibersAnilliiter time perbd 1.616 1 week 0.124 3 months 0.062 6 months 0.031 1 year 0.0155 2 years 0.00062 50 years

If a different time period is needed than shown in the table, multiply the one-year cumulative ' exposure index by the time period. For 2 weeks, multiply by 14/365, etc.

Precaqtions when using Table 3

Conjusion over the way asbestos is reported.

The first and foremost precaution in using Table 3 is this:

DO NOT CONFUSE ASBESTOS LEVELS REPORTED AS: “structures per square millimeter** ( s/mm’) WITH “structures per millfliter** ( s/mL)

These arc very different things, although to the unwarj , they appear to be the same. However, “structures per square milliliter*’ (s/mL) are foe same thing as “structures per cubic centimeter” (s/cc^). See foe last section of this memo for more information on foe way asbestos levels are reported.

At its web site, EPA only reported concentrations as “structures/sqv"'. millimeter.”" They could have given the asbestos concentration as “structures/milliliter** but did not. Thus, it is not easy to compare the EP \ data unless you look at the actual lab sheets, which are posted on the internet at the NYELJP web site.’’

-9-

NYC-WTC_000140267