ALUMINUM METAL DUST

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: 7429-90-5; Chemical Formula: Al

OSHA formerly had no specific permissible exposure limit for aluminum metal dust, although the Agency’s generic 15 mg/m³ TWA limit for total particulate applied. The ACGIH has an 8-hour TWA limit of 10 mg/m³ as total dust for this substance. OSHA proposed a PEL of 10 mg/m³ (total particulate) and 5 mg/m³ (respirable fraction) for aluminum metal dust; however, in the final rule, OSHA is retaining its former 15-mg/m³ total particulate limit for this substance. In its elemental form, aluminum is a white, malleable, ductile metal.

Aluminum metal dust has been shown to present a minimal health hazard, according to results from the McIntyre Foundation’s 27-year study of aluminum oxide dust (discussed in Stokinger 1981a, in Patty’s Industrial Hygiene and Toxicology, 3rd rev. ed., Vol. 2A, pp. 1500-1503). No deleterious lung or systemic effects were observed as a result of exposure to aluminum metal dust having a particle size of 1.2 um at calculated concentrations equivalent to 2 mg/m³ over an 8-hour workshift. Even much higher concentrations (not further specified) over 10- or 20-minute periods produced no adverse effects (ACGIH 1986/Ex. 1-3, p. 22). A comment submitted by the Reynolds Aluminum Company endorses OSHA’s classification of aluminum metal dust under the general dust and particulate heading (Ex. 3-135). NIOSH (Ex. 8-47, Table N4) did not conduct an in-depth review of the health evidence for this substance. OSHA has concluded that aluminum metal dusts are appropriately controlled by retaining the Agency’s PELs of 15 mg/m³ TWA, as total particulate, and 5 mg/m³, as the respirable fraction. OSHA has determined that these limits will provide protection against the significant risk of physical irritation.