Mixture formula justified (AIHCE Extended Abstract).
Am Ind Hyg Assoc J 1996 Jun; 57(6):574-575
In this letter to the editor the author discusses an earlier paper by Williams et al which indicated that the apparent allowable exposure to silica (14808607) using the existing OSHA permissible exposure limit (PEL) varies between 0.033 and 0.098mg/m3 as the silica content varies between 1 and 100%, respectively. The author states that Williams et al failed to note that the PEL equation is mathematically equivalent to the American Conference of Governmental Industrial Hygienists (ACGIH) formula for computing Threshold Limit Values (TLVs) for Mixtures. The author indicates that the respirable mass TLV adopted by the ACGIH in 1970, which is the basis for the current OSHA PEL, incorporated a crystalline silica TLV of 0.1mg/m3 and a respirable dust TLV of 5.0mg/m3. This is consistent with the use of the Threshold Limit Values for Mixtures formula. The author concludes that based on these observations, the use of the mixture formula appears justified.
NIOSH-Author; Exposure-limits; Standards; Regulations; Respirable-dust; Airborne-dusts; Mineral-dusts
American Industrial Hygiene Association Journal