Is it safe to travel for business or leisure to Manhattan following fears about asbestos dust after the attack on, and collapse of, the World Trade Center (WTC)? And should we be worried by recent reports that as many as one in seven people in developed countries have been damaged by exposure to asbestos?
Engineering reports have suggested that the north twin tower originally contained asbestos, as did some 30 storeys of the south tower - but that the asbestos was removed after the 1993 bomb at the WTC.
The Occupational Safety and Health Administration, the main US governmental body dealing with workplace safety, took air and bulk samples in the financial district east of Broadway and south of John Street in the aftermath of the September 11th assaults.
Results for asbestos ranged from "non-detected" to 0.041 fibres per cubic centimetre, with further analysis showing all fibres to be non-asbestos. Occupational Safety and Health Administration found the results "to be consistent with safe and acceptable standards".
In a second "warm" zone, comprising a 90-square block surrounding Ground Zero, asbestos levels were found to be "safe and consistent, ranging from 0.0013 fibres per cubic centimetre to 0.086 fibres per cubic centimetre".
At the "hot" zone, Ground Zero - comprising the remains of the World Trade Centre towers and partially collapsed buildings - air and bulk samples taken by Occupational Safety and Health Administration showed levels ranging from 0.004 to 0.114 fibres per cubic centimetre. The highest reading of 0.114 was directly on the rubble pile.
These readings are regarded as safe given that the permissible exposure limit for asbestos is 0.1 fibres per cubic centimetre as an eight-hour time-weighted average, while a one fibre per cubic centimetre excursion limit over a 30-minute is permitted for short-term exposure.
Despite these safe levels of exposure, the Occupational Safety and Health Administration recommends that "workers in the immediate area of the rubble pile wear respirators".
Meanwhile, the US Environment Protection Agency has been using 3,000-gallon capacity filter vacuum trucks in Manhattan to clean streets, vehicles and buildings of hazardous dust. The highly efficient particulate air filters can capture asbestos and other small fibres, store them in airtight containers and subsequently dispose of them safely.
So it appears that fear of asbestos should not keep us from visiting Manhattan.
But what of that other report that said as many as one in seven people in the West have already been damaged by asbestos? As many as 13 per cent of 160 corpses tested at a Brussels hospital between 1998 and 2000 were found to have traces of asbestos, and experts predicted that asbestos would cause an increased number of fatalities until 2020.
Plaques were found in 14 per cent of corpses and in 20 per cent of male cadavers, while concentrations of more than 1,000 asbestos bodies per gramme of dry lung tissue were found in 13 per cent of the tested sample.
Antii Tossavainen, from the Finnish Institute of Occupational Health, was quoted by the BBC as saying: "We know that occupational asbestos exposure in Western Europe, North America, Japan and Australia was at its peak in the 1970s. Now, recent estimates indicate that 30,000 new asbestos-related cancers continue to be diagnosed there every year. They include some 10,000 mesotheliomas and approximately 20,000 cases of lung cancer."
However, Dr Dan Murphy, director of occupational medical services at the Health and Safety Authority, told The Irish Times: "I don't think this is new information at all because there is a certain amount of asbestos in the air - a very, very tiny amount.
"Very small amounts of asbestos - it being a very indestructible substance - will inevitably get breathed in. We're talking about a fibre here and there.
"This is where all the theories in the past about 'one fibre and you're dead' are absolutely ridiculous. Asbestos, like anything else, is dose-related. If this were not the case, the general population would be coming up with asbestos-related diseases. This is extremely rare, although it is known to have happened even in Ireland, where people living close to an asbestos factory did die of asbestos-related diseases. But they have to be in that kind of situation where they got a hell of a dose."
As for the "asbestos bodies" discovered in the lungs of cadavers, Dr Murphy says we all have them, little asbestos fibres that have been coated by our bodies with a protective layer as a defence mechanism.
For environmental monitoring in New York, see the US Environmental Protection Agency's website: www.epa.gov.
For the Occupational Safety and Health Administration air monitoring link for asbestos testing in different parts of Manhattan, see the Occupational Safety and Health Administration website: www.osha.gov
jmarms@irish-times.ie
