How long has it been known that welding rod exposure causes disease?

Astonishingly, the first published report linking manganese exposure to Parkinson's-type symptoms came out in 1837. In 1932, another published report stated that welding rods containing manganese should not be used and in 1937, an insurance company actually published a welding safety pamphlet stating that manganese in welding fumes caused a disease similar to Parkinson's. In 1963, a toxicologist linked manganese fumes released in the electric arc welding process with Parkinson's and in 1981, the World Health Organization weighed in on the issue, urging the use of safety equipment to mitigate manganese exposure during welding. Although the lawsuits related to welding rod exposure are fairly new, the problem is not.

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