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Home > Resources > The Synergist > SynergistNOW Blog > Posts > News Roundup: Welding Fume Newly Classified as Group 1 Carcinogen
News Roundup: Welding Fume Newly Classified as Group 1 Carcinogen

By Kay Bechtold

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?

Kay Bechtold is assistant editor of The Synergist. 


Fume or UV?

Hi Kay, did they specifically list welding fume or just UV as Class 1? It looks like when you search the classifications on the IARC website, there's a line item for welding fume (as well as one for UV), but the comments on the welding fume line only speak to ocular melanoma from UV exposure. Is it possible that the metals / particulate in the welding fume aren't considered Class 1, and its only the UV radiation they're speaking to?
 on 5/3/2017 12:39 PM by Ben | Flag comment for inappropriate content

Fume and UV radiation

Hi Ben,

Thank you for your comment. I appreciate you helping to keep me on track!

Yes, in the article published online in The Lancet Oncology on April 10, the IARC Monograph Working Group specifically lists both UV radiation from welding and welding fumes in Group 1. The article states, "In the present evaluation, welding fumes and UV radiation from welding were classified as 'carcinogenic to humans' (Group 1)." This is due to "substantial new evidence" from observational and experimental studies that are detailed a little bit further in the article.

It's my understanding that IARC will publish its more detailed assessments later in Volume 118 of the IARC Monographs. I haven't seen an expected publication date for that, but perhaps the classifications on the IARC website won't be updated until that's published?

The summary of IARC's evaluation is available online here: The full article is available free of charge to registered users (but registration is also free).

I hope this helps. Thanks again!
i:0#.f|crmmembershipprovider| on 5/3/2017 2:28 PM by Kay Bechtold | Flag comment for inappropriate content

IARC classification of welding fumes and UVR

Dear Kay and Ben,

we realized that the additional information on the evaluation of welding fumes may have led to some confusion about the exact evaluation statements.

There are indeed two independant evaluations,

"Welding fumes", Group 1 (with sufficient evidence for lung cancer), and

Ultraviolet radiation, Group 1, with the additional information "Volume 118 concluded that ultraviolet emissions from welding are carcinogenic to humans (Group 1). There is sufficient evidence in humans for the carcinogenicity of ultraviolet emissions from welding)" (with sufficient evidence for ocular melanoma).

For better clarity we keep the additional information only for UVR, and not for the welding fumes. Details on Vol 118 of the IARC Monographs (rationale for evaluation and key references) are summarized and freely available in The Lancet Oncology.

Thank you for pointing this out.
Best regards, Kurt
 on 5/19/2017 12:18 PM by Kurt Straif | Flag comment for inappropriate content

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