Memo re: DEP outdoor asbestos air monitoring, Oct 2001

NYC 9/11 Public Portal Document

Beginning September 12“*, DEP has operated a network of outdoor (or “ambient”) fixed air monitors that have been used for monitoring asbestos levels. There are monitors at 3? locations as of today. The locations are shown on the map. The map and all sampling results to date from the sites shown on this map are on DEP’s website: www.nvc.gov/dep.

The monitors capture air samples that are tested for the presence of fibrous material such as asbestos. The samples are tested using the PCM method [DEFINE]. The PCM sampling method does not actually show the presence of asbestos; PCM shows the presence of some type of fibrous particle. PCM-tested samples that show more than 0.01 fibers per cubic centimeter are re-tested using the TEM test [DEFINE]. The TEM test shows whether or not the fibers collected in the sample are actually asbestos fibers.

There is no national standard for asbestos in OUTDOOR AIR. There is a national standard for asbestos in indoor air. That standard is 0.01 fibers per cubic centimeter. It was developed to establish what amount of asbestos is considered safe in a confined environment where people live and work, breathing re-circulated air hour after hour. Used as a benchmark for outdoor air, the standard is very conservative. If there were a standard for ambient air, it would be much higher than 0.01.

Based on over three/four/five??? hundred samples tested using PCM, and [HOW MANY] samples tested using TEM, public health experts are very confident that asbestos levels in ambient air outside of the restricted zone do not pose a threat to human health. Short-term exposure to asbestos, even at levels much higher than 0.01, carries an extremely low risk of causing asbestos-related illness.

DEP’s monitors are all outdoor. At this point, there are no stationary monitors in place within buildings. Judging from phone calls, conversations, and comments at community meetings, there are many individuals who are not clear on the division of clean-up and testing responsibilities inside of buildings. I would like to re-state a few basic facts regarding cleanup.

Before allowing occupants in any residential or commercial building near the Ground Zero [MORE SPECIFIC?], the City required building owners to take these steps:

o Assess the building’s structural strength and stability; o Restore gas and electrical service; o Restore building water service, including flushing, re-filling and cleaning roof tanks as necessary; o Assess the presence of hazardous materials such as asbestos, and remediate as required under applicable regulations; o Inspect, clean and repair mechanical and HVAC systems.

Although city, state and federal agencies have provided oversight and guidance, “indoor tasks” have been and remain the responsibility of building owners and occupants. For

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