NYC-WTC_000209237

NYC 9/11 Public Portal Document

Liberty Mutual .

Industrial Hygiene Air Sample Results Summary for Week of 1/25/02 to 2/1/02

Attached is a summary of the laboratory results completed during the week of January 25, 2002 to February 1, 2002. The air samples were collected by ATC associates at the World Trade Center site.

The majority of the samples collected by ATC are “personal samples”, meaning that the worker wore the sampling device. In addition, the most of results have shown exposure levels to be below shift adjusted occupational exposure limits. The exceptions were;

A lead concentration of 242% of the shift adjusted OEL on a Torch Cutter in depression on the spot of tower 2, e An arsenic concentration of 214% of the shift adjusted OEL on a Torch Cutter in depression at tower 2, o Diesel exhaust particulate concentrations at 214% and 104% of the shift adjusted OEL on a Torch Cutter in depression at tower 2 and Grappler Operator in depression at tower 1, respectively, o An asbestos concentration at 198 % of the shift adjusted OEL* on a spotter on surface at 4 WTC, and o A quartz concentration of 104% of the shift adjusted OEL on a Laborer in a pit at Liberty and Washington Streets.

In addition, the following results are at or above 50% of the shift adjusted OEL (but below 100% of the shift adjusted OEL). The operations associated with these results should receive attention to ensure that these results are an accurate reflection of actual exposures and that feasible steps are taken in an attempt to ensure that exposures do not elevate over time;

* Diesel exhaust particulate concentrations of 96 %, 68%, 59%, and 54% of the shift adjusted OEL on a Truck Washer at pier 25, a Truck Washer at West St, a Loader Operator in the depression, and a Spotter on the surface at pier 25, respectively, and ® Asbestos concentrations of 70 % and 60% of the shift adjusted OEL on a Spotter in depression at tower 1 and Grappler Operator in tower 1.

Some of the columns in the attached summan’ may require explanation:

Analyte Class - This column includes general category of the agents (substances) which were sampled.

# of Samples - This indicates how many individual samples were collected for the agent class listed.

# of Analysis - This is the number of individual analyses performed. If only one analysis is performed on each sample, then the number of analytes will equal the number of samples. However, most samples are analyzed for more than one agent as follows:

' The fibers present may or may not be asbestos. This sample is being analyzed further to confirm the presence of asbestos. That result is pending.

CITY_21MC100_002855871

NYC-WTC_000209237