What are the permissible exposure limits for asbestos?
The following exposure limits are for the weorkplace environment for fibers longer than 5 micrometers.

OSHA - the legal airborne permissbale exposure limit [PEL] is 0.1 fiber/cc [fiber per cubic centimeter] averaged over an 8-hour workshift and 1 fiber/cc not to be exceeded during any minute work period.

NIOSH - the recommended airborne exposure limit is 0.1 fiber/cc [fiber per cubic centimeter] averaged over an 10-hour workshift.

ACGIH - the recommended airborne exposure limit is 0.1 fiber/cc [fiber per cubic centimeter] averaged over an 8-hour workshift.

Asbestos is a CARCINOGEN in humans. There may be NO safe level of exposure to a carcinogen, so all contact should be reduced to the lowest level possible.