Naturally-Occurring Asbestos - Air Monitoring

The Air Resources Board (ARB) conducted air monitoring in several locations in California to determine the levels, or concentration, of asbestos in the air at selected sites. This monitoring data was used to help evaluate the extent of the public's exposure to asbestos.

It is important to understand that these results are individual measurements at specific sites and do not represent what the average or typical asbestos exposures may be in any broad area. Estimated potential cancer risks assume that a person would be continuously breathing those levels for 24 hours a day for 70 years. This should not be interpreted to mean that it is necessary to be exposed to asbestos for 70 years in order to contract asbestos-related cancer. Rather, the potential cancer risk is a high-end estimate of the number of cases in a population of a million people exposed over a lifetime. It should be noted that we do not have approved methodologies or health values for estimating potential cancer risks from short-term exposures.

To put risk numbers into perspective, the estimated potential cancer risk from air toxics on a statewide average is about 750 chances in a million. An individual's chances of getting cancer over his or her lifetime from all causes is estimated to be about 1 in 5 in California or 200,000 chances in a million.