How likely is sulfur dioxide to cause cancer?
There are no studies that clearly show carcinogenic effects of sulfur dioxide in people or animals. Studies have investigated workers in the copper smelting and pulp and paper industries, but the results are inconclusive since the workers were also exposed to arsenic and other chemicals. The one available animal study suggests that sulfur dioxide may be a carcinogen in mice. The International Agency for Research on Cancer (IARC) has classified sulfur dioxide as Group 3, not classifiable as to human carcinogenicity.
