NYC-WTC_000204893

NYC 9/11 Public Portal Document

organic vapor samples also picked up Freon, which is a refrigerant, used in the air conditioning systems of the buildings. There are reported to be several large tanks of Freon in the basement of the building that are thought to be intact but that has not been confirmed.

RESULTS OF SAMPLING BY OTHER ORGANIZATIONS

Other organizations are reporting results similar to those obtained by the lUOE. Of particular note, the EPA has picked up several ambient air samples for asbestos that were analyzed by transmission electron microscopy and also exceeded the EPA clearance level for asbestos abatement. They have found that levels have been generally getting lower, however. Most of the sampling that has been conducted for asbestos around the site has been analyzed by optical microscopy, which is not as sensitive.

The EPA has also reported finding three elevated readings for lead and three for chromium. It is important to note that the EPA’s acceptable level for lead is considerably lower than OSHA’s because the agency is concerned with long term exposure of the general public, not work exposure.

The EPA has noted that all four of the samples taken for dioxin on September 16'*’ showed all levels at or above the EPA’s removal action guideline, which is based on a 30-year, 24-hour exposure risk scenario. The samples were reported to have been collected directly in the plume of smoke. Dioxin is an extremely toxic compound and is generated by combustion of plastics.

CONCLUSIONS

The results of the air sampling conducted by the lUOE and by others support the earlier recommendation by the lUOE’s team that Operating Engineers should be wearing respiratory protection. The results indicate that the half-face respirator with high efficiency dust cartridges that also protect against organic vapors and acid gases (PIOO/OV/AG) are sufficiently protective. This is also the conclusion of NIOSH in a policy statement from September 27, 2001.

There has been disagreement among some agencies about the necessity of protection against organic vapors and acid gases because the levels measured have been generally low. The position of the lUOE team is that the potential exposure to dioxin in the smoke warrants organic vapor protection. Additionally, the cartridges will protect against odors from bodies. The presence of large quantities of Freon means that hydrochloric and hydrofluoric acid can be generated in the presence of heat. Consequently, workers need to be protected from acid gases, too.

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NYC-WTC_000204894