With EPA funding, Berman has developed a proposed protocol for predicting exposure, and therefore assessing risk, using the wealth of new research data that has arisen over the past 2 decades. He presented his findings during a standing-room-only breakout session May 25 at the American Industrial Hygiene Conference and Exposition (AIHce) in Anaheim, Calif.
"The protocol that we've developed stresses that risk relates to fiber number concentrations rather than mass concentrations," said Berman. The new approach stresses the need to recognize that longer and thinner asbestos structures are more tied to risk than shorter fibers.
Traditional risk assessments that fail to distinguish the size and shape of asbestos structures may be doubly misleading, according to Berman.
"It is important to pick out the subset of fibers that actually contributes to the induction of disease," said Berman. "There are many more short ones in the world, so if you just count everything you'll get a lot of short fibers that are not tied to risk."
Berman's findings could have implications for how EPA defines and regulates asbestos: The agency currently defines "asbestos-containing material" as any material containing more than 1 percent asbestos by weight. Under Berman's proposed protocol, the type of fiber rather than the weight of all fibers is a more reliable predictor of risk. He said that in some cases the current definition may be overprotective and in others not protective enough.
Asked if he thought EPA might be preparing to redefine asbestos-containing material, Berman replied that he thinks it is a subject the agency may well consider in the future.
