Reduction of the biological potential of chrysotile asbestos arising from conditions of service on brake pads

Data exist that show that chrysotile asbestos does not retain its mineral properties, or biological activity, at temperature far below the olivine transformation point. Temperatures hundreds of degrees below this point cause the mineral to lose structural water with accompanying crystal structure degradation.

Studies have shown that thermal treatment and mechanical manipulation of chrysotile alters both its surface and structure. Service conditions created on brake pads both heats and tears down the fiber. Chrysotile subjected to these severe conditions cannot, and does not, retain its natural properties. Chrysotile biological activity is thereby greatly reduced, and can become virtually nil hundreds of degrees below the olivine transformation temperature. Complete transformation of the mineral is not required to result in loss of activity.

Exposure to brake wear debris, which has been created as the result of these forces, may be associated with little or no risk of asbestos disease. Blowouts and cleanups of wear debris, both visually dusty work practices, might constitute no asbestos hazard to workers.