Seventeen scientists from 10 countries met earlier this year at the International Agency for Research on Cancer (IARC) to evaluate the carcinogenicity of welding fumes and UV radiation from welding. IARC estimates that 11 million workers have “welder” in their job titles, and approximately 110 million others likely incur welding-related exposures. The IARC working group classified both welding fumes and UV radiation from welding as Group 1 carcinogens, the agency’s designation for agents that carry sufficient evidence of carcinogenicity in humans. This classification signals a change in the agency’s stance on welding fumes; when IARC previously assessed their carcinogenicity in 1989, the agency classified welding fumes in Group 2B as “possibly carcinogenic to humans.” IARC’s position on UV radiation from welding remained the same: it was previously classified as a Group 1 carcinogen in an IARC monograph published in 2012.

What are the practical issues in minimizing welding fume exposures? “The first and best strategy is to control hazards at the source; engineering controls and other measures can further augment reductions at the source,” writes Michael J. Keane, NIOSH research chemical engineer, in the April 2017 Synergist. Keane’s article “Source Reduction” discusses how substituting a lower-emission welding process for a high-emission welding process can help reduce emissions of fumes and toxic metals as well as decrease operating costs.

Recent research on welders’ exposures to airborne manganese in welding fumes suggests the OSHA’s current permissible exposure limit (PEL) for manganese fume of 5 mg/m³ ceiling may not adequately protect workers. Researchers from the Washington University School of Medicine in St. Louis found neurological signs in welders with estimated manganese exposures as low as 0.14 mg/m³. ACGIH recommends a limit of 0.02 mg/m³ for manganese.

Speaking of manganese exposure in welding, Frank Mirer, regular Synergist contributor and professor in the CUNY School of Public Health in New York, recently wrote about the controversy over the association of manganese exposure in welding and Parkinson’s-like disease. “The toxic potential of manganese has long been recognized, but the recognized toxic potency, as reflected in occupational exposure limits, has evolved over time,” he writes. Mirer discusses manganese as a paradigm for evaluating OELs, and for how research evolves.

This summer, the Synergist staff will begin putting together the editorial calendar for 2018. What other welding-related topics would you be interested in reading about in The Synergist or AIHA’s e-newsletter, The Synergist Weekly?