The study suggested that present safety standards may not precisely protect welders from the dangers of the job. “We identified that chronic exposure to manganese comprising welding fumes is linked with progressive neurological symptoms like slow movement and difficulty speaking,” says Brad A. Racette, M.D., a lecturer of neurology and the senior author of the study. “The more exposure you possess to welding fumes, the more swiftly those symptoms progress over time.”
At big levels, manganese – a core component of vital industrial procedures like steelmaking and welding can cause manganism, a severe neurologic trouble with symptoms similar to the Parkinson’s ailment, comprising clumsiness, slowness, mood changes, tremors, and difficulty speaking and walking. The trouble of manganism drove the Occupational Safety and Health Administration decades ago to set clear standards limiting the volume of manganese in the air at the workplaces.
While such safety standards are considered to have eradicated manganism as an occupational hazard, scientists who study the effects of manganese have long identified that there might still be few health effects at levels much lesser than what is allowable per OSHA standards.
“Numerous scientists consider what is allowable as too high a level of manganese, but till now there really were not data to prove it,” says Racette, who also is an executive vice chairman in the Department of Neurology. “This is the first study that reveals clinically relevant health effects that are happening at estimated exposure that are an order of magnitude lesser than the OSHA limit.”
Racette and his team studied around 886 welders at three worksites in the Midwest – two shipyards and one hefty-machinery fabrication shop. Each welder filled out a precise job history questionnaire, which the scientists used to estimate each participant’s exposure linking the estimated manganese exposure for specific job titles with the volume of time spent in each of the job.
Each participant also underwent at least two of the standardized clinical evaluations of motor function spaced a year or more apart and utilizing the Unified Parkinson’s Disease Rating Scale. The estimations were performed by trained neurologists looking for symptoms of neurological damage like gait instability, stiffness of muscle, reduced slow motion and facial expressions.
The most troublesome aspect of the study, Racette says is that the neurological symptoms showed up in people with a calculated exposure of only 0.14 milligrams of manganese per cubic metre of air, far below the security standard set by OSHA at 5 milligrams per cubic metre. In previous years, the American Conference of Governmental Industrial Hygienists recommended a limit of 0.02 milligrams of manganese per cubic metre. Few companies already are attempting to ensure their workers exposures below that level by enhancing ventilation, mandating personal protective equipment and utilizing low-manganese welding wire
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