From: "Barry Castleman, ScD" (firstname.lastname@example.org)
Subject: Re: [OEM] EPA Monitoring NYC H2O & Air
Date: Sun, 23 Sep 2001 22:17:25 -0400
EPA sources have variously been reported as saying that 1% asbestos is "safe", the minimum level of concern in dust samples, or as here ("the amount above which material is considered asbestos-containing"). The fact that 37/101 dust samples from the WTC site analyzed had over 1% asbestos is alarming. It shows that the potential for high bursts of occupational exposure to asbestos exist, which may or may not be reflected in air sampling of occupational and environmental exposures. )From this one can only hope that the workers involved are wearing proper respiratory protection and wash and have their clothes changed before going home from work.
UK industrial hygienist Robin Howie (email@example.com) writes, "From Newsweek's 'Asbestos Alert' article of 14th September a sample of dust containing 4.5% of asbestos was collected near Ground Zero and other samples containing more than 1% asbestos have been collected. It also appears that the EPA considers a 1% asbestos content as acceptable...A 1988 study by John Addison of the Institute of Occupational Medicine concluded that aerosolisation of soils containing 0.001% of asbestos could generate respirable fibre concentrations of 0.01-0.02 fibres/ml in a dust cloud of 5 mg/m3. Addison demonstrated that for a 1% asbestos content in sand and a cloud concentration of c 5 mg/m3 airborne fibre concentrations were c 7 f/ml for chrysotile and c 20 fibres/ml for amosite and crocidolite. Note that a 5 mg/m3 cloud would effectively be invisible in normal lighting conditions."
Dust samples slightly less than 1% plutonium would still be high-level nuclear waste, where DID this 1 percent asbestos "threshold limit" come from? While additional information on this would be most welcome from the EPA, I recall that there was a 1% limit included in the "ban" on sprayed asbestos insulation in EPA hazardous air emissions standards issued in 1973. Could it be that this limit is somehow regarded in 2001 as having scientific support as "safe" or anything of the kind, despite the general acceptance by EPA that there are no non-zero thresholds of inhalation exposure that are considered free from cancer risk?
Another claim that has been made by a few defamers of Dr. Selikoff is that the replacement of asbestos insulation contributed to the speed of the collapse of the WTC buildings. This disregards the fact that the temperature limits for thermal degradation are higher for the replacement materials (variously reported as mineral wool, rock wool) than for all the asbestos minerals.
Whitman elaborated on the repeated monitoring of ambient air both at the World Trade Center disaster site and the surrounding area. To date the Agency has taken 97 air samples from 11 separate fixed monitoring sites in and around the "hot zone" and elsewhere in lower Manhattan, and four fixed monitoring sites located in New Jersey downwind from the blast. Only seven samples taken at or near ground zero have had marginally higher levels of asbestos that exceed EPA's level of concern. All rescue workers in this restricted-access area are being provided with appropriate safety equipment. Ambient air monitoring in the Financial District, where this week people have returned to work, show levels of asbestos that are below Agency levels of concern. Whitman detailed dust sampling undertaken thus far at the World Trade Center site, and confirmed that EPA has done a total of 101 dust samples, of which 37 were slightly over the one percent asbestos (the amount above which material is considered asbestos-containing). EPA has continued to use its 10 High Efficiency Particulate Arresting (HEPA) filter vacuum trucks, especially in areas where dust samples show any elevated levels of asbestos. Of the 16 samples taken in the Battery Park City area, a residential community within two blocks of the disaster site, 12 showed slightly elevated levels of asbestos. After using the HEPA Vac trucks to clean streets and surfaces in Battery Park City, repeat sampling in the area showed asbestos levels that fall below concern amounts. EPA will continue to monitor this area. The HEPA Vac trucks were also used to vacuum lobbies of federal buildings near the disaster site prior to having workers return.