NYC-WTC_000232919

NYC 9/11 Public Portal Document

n Industrial Hygiene Air Sample Results Summary for Week of 04-15-02 to 04-19-02

Attached is a summary of the laboratory results completed during the week of April 15, 2002 to April 19, 2002. The air samples were collected by ATC associates at die World Trade Center site.

The majority of the samples collected by ATC are “personal samples”, meaning that die worker wore the sampling device. In addition, the majority of results have shown exposure levels to be below shift adjusted occupational exposure limits. Those results which were higher than the shift adjusted occupational exposure limits were:

• Three Quartz concentrations as follows: • 791 % of the shift adjusted OEL on a spotter at WHC 1 Depression. • 625 % of the shift adjusted OEL on a laborer WTC 5, B2. • 279 % of the shift adjusted OEL on operator middle of south slurry wall

Three Diesel exhaust fume concentration as follows: • 225 % of the shift adjusted OET on a laborer in WTC 5. • 212 % of the shift adjusted OET on a bobcat operator in WTC 5, B2. • 145 % of the shift adjusted OEL on a laborer cleaning beams WTC 5, Bl.

In addition, the following results were 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 lliese results are an accurate reflection of actual exposures and that feasible steps aie taken in an attempt to ensure that exposures do not elevate over time;

• Five Quartz concentrations of 96 %, 92 %, 88 %, 79 % and 70 % of the shift adjusted OEL on a laborer in WTC 6, B2- core drilling, area- mid bridge, WTC 5 torch cutting, WTC 5 Bl- scaffold area, WHC 5 , B2 breaking concrete. • Four Diesel Exhaust Particulate concentration at 85 %, 71 %, 71 %, 51 % and 50 % of the shift adjusted OEL on a torch cutter on scaffold at truck exit, laborer WTC 5 sublevel. Torch cutter in depression WTC 5, excavator operator WTC 4.

Some of the columns in the attached summary 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:

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CITY_21MC100_005081631

NYC-WTC_000232919