NYC-WTC_000204880

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan December 13, 2002 Air Sampling for VOC’s Page 3 Francis Lewis High School (0374) ATC Project No. 15-19125-0374

Toluene

Toluene was detected in four indoor samples at a concentration of 1 ppb, this was the same as the outdoor sample concentration. One indoor sample (Basement by the elevator) contained toluene at 3 ppb. There is no EPA screening level for toluene however, EPA has established, based on experimental data, a Reference Concentration for Chronic Exposure (RfC) of 0.4 milligrams per cubic meter (0.4 mg/m^). This is equal to 106 ppb. The levels in these samples are below the RfC for toluene.

Total Xylenes

There are three forms of xylene, meta-xylene, para-xylene and ortho-xylene (m-xylene, p-xylene, o-xylene) present in combination in the samples. The analyses are separated into two parts, m/p-xylene and o-xylene. The results in the table are the sums of the concentrations the two xylene concentrations reported for each sample. Indoor concentrations ranged from <1.4 ppb to 5 ppb. The outdoor concentration was <0.8 ppb. The Federal Agency for Toxic Substances and Disease Registry (ASTDR) has calculated a Minimal Risk Level (MRL) for xylenes of 0.1 parts per million (100 ppb) for chronic inhalation exposure. The levels in these samples are below the MRL for xylenes.

Ethylbenzene

Ethylbenzene was detected in the indoor samples in a concentration range of <0.2 to <1 ppb, it was not detected in the outdoor air. The EPA RfC for ethylbenzene is 1 mg/n? (equal to 231 ppb). The levels in these samples are below the RfC for ethylbenzene.

Methyl tert-Butyl Ether (MTBE)

MTBE is a common gasoline additive (“octane booster”). The indoor concentration range was <0.6 ppb to 5 ppb, the outdoor concentration was 1 ppb. The MRL for chronic MTBE exposure is 700 ppb. The levels in these samples are below the MRL for MTBE.

The Occupational Safety and Health Administration (OSHA) has a Permissible Exposure Limits (PEL) for benzene (1 ppm), toluene (200 ppm), xylenes (100 ppm) and ethylbenzene (100 ppm) There is no PEL for MTBE. The OSHA PELs are intended for industrial exposures and are not applicable to school populations.

The sample collected in the Basement by the elevator contained the highest indoor concentrations of all of the five VOCs discussed above, however these concentrations were very low.

Tetrachloroethylene (PERC) and trichlororethylene (TCE) were included in the analyte panel and both compounds had been previously detected in the ground water and soil gas. TCE was not detected in any of these samples. PERC was found just above the limit of detection in only the sample collected in the Basement by the elevator, it was not detected in any of the other samples.

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