AWS-commissioned Study on Welding and Exposure to Manganese
Does Scientific and Medical Literature Support Concerns That Some Have Expressed About Exposure to Manganese in Welding Fume?
In July 2004, the AWS Safety and Health Committee engaged an outside independent expert, Woodhall Stopford MD, MSPH, of the Duke University Division of Occupational and Environmental Medicine, to review the literature of published articles related to the neurotoxicology of manganese, particularly including manganese found in welding fume. The Committee's intention was to obtain an objective appraisal of the relevant literature by an authoritative expert, and to receive a written report that would reflect the expert's own views independent of those of AWS, the Safety and Health Committee, any Committee member, or any organization or person with a direct interest in welding matters. The Committee's plan from the outset was that it would promptly make Dr. Stopford's report part of the public record whatever its conclusions, and regardless of whether the Committee, or any Committee member, would or would not ultimately agree with all of the conclusions or with any of Dr. Stopford's specific findings or stated views. Dr. Stopford has now completed his report which finds:
– Parkinson's Disease and manganism are separate and distinct illnesses.
– Published research shows that exposures associated with manganism have occurred primarily in nonwelding occupations such as the mining and manganese alloy fabrication industries.
– Studies have not supported that welders have a higher incidence of Parkinson's Disease compared to the general public or that welding is a risk factor for Parkinson's Disease.
– Studies have not supported that welders have a higher incidence of an earlier onset of Parkinson's Disease compared to the general public.
– Studies of Parkinson's Disease patients have not supported a relationship between welding and Parkinson's Disease.
AWS and the members of its Safety and Health Committee have commissioned and will continue to commission research by independent outside experts to promote welding safety and health. For example:
– Since 1998, the Safety and Health Committee has sponsored research by the Harvard School of Public Health studying factors influencing the transport of manganese in animals. The result of the first study showed that the amount of iron in the lungs affects the rate of transport of manganese from the lungs to the blood. In the iron exposed animals, the movement of manganese from the lungs to the brain was reduced. This is significant because when welders are exposed to manganese in welding, iron is also present. The implication is that less manganese is transported from the blood to the lung when the manganese is complexed with iron, as it is in welding fume, as compared to the transport of manganese without the presence of iron, as occurs in nonwelding occupations such as mining and smelting operations.
– Research for the 13th volume of the AWS series, Effects of Welding on Health, is currently underway. The series, administered for more than a quarter century by the AWS Safety and Health Committee, is an ongoing, comprehensive review of the worldwide medical literature related to welding and health. The 1st volume, published in 1979, reviewed the worldwide medical literature published between 1940 and 1977. Subsequent volumes have covered periods of 2 to 3 years, with volume 13 covering the years 2000 through 2002.
– Other important safety and health related research publications sponsored by AWS include: The Welding Environment (1973), Fumes and Gases in the Welding Environment (1979), Characterization of Arc Welding Fume (1983), and Toxicity of Welding Fume in Rats (1985).