Study finds no elevated lung cancer risk for hard metal workers

Hard metal industry workers do not face an increased risk of lung cancer, according to research conducted by the University of Pittsburgh Graduate School of Public Health. The research involved more than 32,000 workers from the U.S., U.K., Austria, Germany, and Sweden.

Previous studies have suggested that ingredients in hard metal increase the risk of lung cancer.

“Our findings will affect regulatory agencies and how they set exposure standards,” said principal investigator Gary M. Marsh, PhD, professor of biostatistics at Pitt Public Health and director and founder of the school’s Center for Occupational Biostatistics & Epidemiology.

“It is very good news that the workers in this industry are not at increased risk of death due to the materials used in their occupation, both for the employees and for the hard metal industry.”

Workers at three companies and 17 manufacturing sites were involved in the study coordinated by Pitt Public Health.

Hard metal typically is made by heating tungsten and carbon to form tungsten carbide powder, then adding powdered binders such as cobalt or nickel. Cobalt has been shown to cause cancer in animals and also can be a serious lung irritant. Workers wear closed hoods with full respirators when handling the powdered metals without technical controls.

On average, the study found no increased risk of death for hard metal workers, including those who had worked in the industry for decades and those who worked in the industry before modern respirators.

The researchers found small excesses in lung cancer mortality among short-term workers compared with long-term workers.

“These findings in short-term workers are unlikely due to occupational factors in the hard metal industry,” said Marsh, who also is a professor in the departments of epidemiology and clinical and translational science at Pitt. “Instead they are more likely due to differences in lifestyle and behavior that could impact lung cancer risk, such as higher smoking rates.”

Also, the study found that exposure levels for tungsten, cobalt, and nickel were all below the standards set by the American Conference of Governmental Industrial Hygienists and recommended by OSHA.

The results of the study will be published in an upcoming issue of the Journal of Occupational and Environmental Medicine as a series of eight articles.