Exposure to chemical agents in Swedish aluminum foundries and aluminum remelting plants--a comprehensive survey.

Abstract

Secondary aluminum melting is mainly performed in sand, die, and static die-casting foundries and remelting plants. In seven Swedish foundries and two remelting plants, the exposure and area concentrations of total dust, metals, organic gases, and vapors were determined mainly as daily, time-weighted averages (TWAs). For most combinations of jobs and agents, the exposure levels were well below the current threshold limits suggested by the American Conference of Governmental Industrial Hygienists (ACGIH). However, high exposure levels of mineral oil mist (geometric mean [GM] = 0.6 mg/m3) were observed in the die-casting process, with a maximum of 4 mg/m3. The findings were similar for total dust (GM = 5.1 mg/m3) and crystalline quartz (GM = 0.05 mg/m3) during molding operations in the sand foundries, maximum air concentrations being 31 mg/m3 and 0.22 mg/m3, respectively. Other agents which occasionally reached high exposure levels included furfuryl alcohol (up to 23 mg/m3 during furan binder use in sand foundries), aniline (up to 2.6 mg/m3 during thermal degradation of cold-box binders), and dimethylethylamine (up to 9 mg/m3) in the cold-box process used in static die-casting and sand foundries. The average aluminum exposure levels (GM = 0.043 mg/m3) were low in all foundries, individual values not exceeding 0.94 mg/m3. The exposures to metals were below 10 percent of their threshold limits. Similarly low levels were detected of polyaromatic hydrocarbons, phenol, formaldehyde, methylenebisphenyl diisocyanate, and phenylisocyanate. In the aluminum remelting plants, a few high exposure levels of total dust (GM = 1.4 mg/m3) up to 8 mg/m3 were detected in furnace workers. Aluminum and other metals were well below 10 percent of their threshold limits, with the exception of a few high concentrations of manganese, up to 0.14 mg/m3. The between-worker variability (GSDB) in the foundries for total dust, aluminum, and oil mist were on the order of 3-4. The heterogenicity of secondary aluminum melting requires assessment of a wide variety of chemical agents. For certain exposures, technical and medical monitoring programs are still needed.