COPPER FUME

OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.

CAS: 7440-50-8; Chemical Formula: Cu

The current OSHA limit for copper fume is 0.1 mg/m³ as an 8-hour TWA. Since OSHA adopted this limit in 1971, the ACGIH has increased the recommended TLV to 0.2 mg/m³ as an 8-hour TWA. The ACGIH’s previously recommended TLV of 0.1 mg/m³ was based on a personal communication (Whitman 1957 and 1962, as cited in ACGIH 1986/Ex. 1-3, p. 146) that reported that the taste perception of welders was altered when they were exposed to copper fume at levels ranging from 1 to 3 mg/m³ for short periods but that exposure to from 0.02 to 0.4 mg/m³ did not cause such complaints (ACGIH 1966/Ex. 1-13). At the time, the ACGIH judged the 0.1 mg/m³ TLV to be “sufficiently low to provide freedom from irritation from the fume by a reasonable margin” (ACGIH 1966/Ex. 1-13). NIOSH (Ex. 8-47, Table N1) concurs that OSHA’s 0.1 mg/m³ limit is appropriate. Copper is a reddish-colored metal.

In 1972, the ACGIH received a personal communication from a member of the U.K. Industrial Hygiene Unit, Her Majesty’s Factory Inspectorate (Luxon 1972, as cited in ACGIH 1986/Ex. 1-3, p. 146) reporting that employees exposed to copper fume at levels up to 0.4 mg/m³ during welding and copper metal refining operations experienced no ill effects from exposure. Based on this additional evidence, the ACGIH increased its TLV for copper fume to 0.2 mg/m³ in 1975.

Commenters to the docket urged OSHA to revise the PEL for copper fume to the ACGIH limit. BP America (Ex. 8-57; Tr. pp. 9-126 to 9-127) argued that the Agency should increase its PEL even though the only basis for doing so was a personal communication to the ACGIH TLV Committee. In response to these commenters, OSHA reiterates the position described in the introduction to this section (i.e., that the Agency must demonstrate that exposed workers will not be placed at increased risk even after the limit has been raised). Because the personal communication on which the ACGIH has based its increased limit cannot be examined to determine information of this type, OSHA cannot consider raising the limit at this time.

OSHA concludes that the evidence cited by the ACGIH (1986/Ex. 1-3) in support of the increase in its TLV-TWA for copper fume is not sufficient to support an increase in OSHA’s PEL for this substance. OSHA reasons that the ACGIH’s action was based largely on a personal communication, which makes it impossible for the Agency to evaluate the evidence appropriately.