The Occupational Safety and Health Administration (OSHA) is amending the existing standard, which limits occupational exposure to hexavalent chromium (Cr(VI)). The final rule, which became effective on May 30, 2006, establishes an 8-hour time-weighted average (TWA) exposure limit of 5 micrograms of Cr(VI) per cubic meter of air (5 µg/m³). This is a considerable reduction from the previous Permissible Exposure Limit (PEL) of 1 milligram per 10 cubic meters of air reported as chromium oxide, which is equivalent to a limit of 52 micrograms as Cr(VI).