After concern was expressed in the Netherlands about the scientific validity of many of its occupational exposure limits (OELs), the “International Committee on Updating of OELs” (subsequently referred to as the Dutch Committee) was set up in 1997 to reassess the health protection offered by the national limit values (Maximum Allowable Concentration or MAC values) contained in the 1994 Dutch MAC list. Most had been adopted in the 1970s from threshold limit values (TLVs) set by the American Conference of Governmental Industrial Hygienists (ACGIH). Over the subsequent 10 years the Dutch Committee evaluated the available toxicity data on almost 200 substances, recommending health-based OELs whenever possible. [The resultant reports on individual substances have featured regularly in the pages of Toxicology and Regulatory News over the years.] In a recent overview of the programme, it was noted that only about 40% of compounds met the Committee’s criteria for a health-based OEL, and that “many older MAC values were either too high or not scientifically supported”. For the 66 substances for which a health-based OEL was derived, the corresponding TLV in the 2006 ACGIH list was higher by a factor of two or more for 55 (83%) of the substances and by ten or more for 21 (32%) of the substances (Stouten H. et al., American Journal of Industrial Medicine 2008, 51, 407). {176605}

The above item is taken from the June 2008 issue of Toxicology and Regulatory News which is sent automatically to members of bibra (click here for more details).