Autumn Seminar on Low Level Asbestos Exposures
On October 17, 2007, a technical seminar was held in Belgravia (London) by the British Occupational Hygiene Society (BOHS) on the subject: Low Level Exposures to Asbestos.1 Topics on the agenda included lung cancer, mesothelioma, risk assessment, environmental asbestos levels and airborne asbestos in CLASP (school) buildings.
During highly technical presentations by Andy Darnton, Bill Sanderson, Robin Howie, Alan Jones and Jean Prentice conflicting views were expressed on:
- what is definitively known about the links between asbestos exposure and the occurrence of lung cancer;2 whereas the HSE previously estimated 2 UK cases of lung cancer : 1 mesothelioma, currently it is believed that the ratio is 1 lung cancer : 1 mesothelioma. On the issue of a threshold for lung cancer, Andy Darnton postulated that there “may be” a threshold below which exposure to asbestos does not cause lung cancer;3 this was hotly debated;
- the reliability of the risk model for mesothelioma advanced in 1991 by the Health Effects Institute;
- the prevalence of “spontaneous” cases of mesothelioma;
- the comparative risk of lower exposures over long periods vs. short intense exposures;
- methods for improving the sensitivity of sampling procedures. Industrial hygienist Robin Howie suggested: sample for longer, sample at higher flow rates, count more fields, reduce filter area;
- the concepts, equations and language used to express risk;
- the reliability of sampling conducted in CLASP type schools which showed “acceptable” levels of contamination.
Delegates at the session included health and safety specialists, civil servants, insurers, asbestos analysts and consultants. Some of the powerpoint presentations are now on the BOHS website.4 For further information contact Bill Sanderson, email: bill.sanderson@uk.bureauveritas.com
November 18, 2007
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1 http://www.bohs.org/eventDetails.aspx?event=116
2 The presentation: Lung Cancer & Asbestos by Bill Sanderson can be viewed online at: the BOHS website (file 891)
3 He clarified this by saying that the level of any threshold will be fiber-type dependent and any actual threshold for amphibole is likely to be very low. Darnton's presentation: The Quantitiative Risks of Mesothelioma in Relation to low-level Asbestos Exposure can be viewed online at: the BOHS website (file 892)
4 Identification of Fibres on Filters by Jean Prentice can be viewed online at: the BOHS website (file 884)
