A comparison of U.S. and Japanese occupational exposure limits for chemical substances and biological monitoring values

This article compares current values for occupational exposure criteria in Japan and the United States and briefly describes the Japanese organization. The values recommended by the committee of the Japan Society for Occupational Health (JSOH) correspond fairly closely with those of the American Conference of Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV®) and biological exposure index (BEI™) committees, perhaps because much of the information is drawn from the same database. For only six substances do the limits differ by more than a factor of 10, while for 121 substances the limits differ by less than a factor of 2. For 28 substances the TLV exceeds the JSOH occupational exposure limit (OEL) by a factor of between 2 and 10, while for 18 the TLV is correspondingly less than the JSOH OEL. Provisional values are given, or changes proposed, for 29 substances. The principal biological limits for mercury are identical, while those for lead and hexane differ by less than a factor of 2. Classification of carcinogens differs slightly, but the numbers of proven human carcinogens are similar, as are the total numbers considered suspect.