Formaldehyde, a chemical to which an estimated 1 million European Union workers are exposed at work, definitely causes cancer in humans, officials say. The International Agency for Research on Cancer (IARC) has upped its assessment of the chemical to ‘Group 1’. Previous evaluations, based on the smaller number of studies available at that time, had concluded that formaldehyde was probably carcinogenic to humans, but new information from studies of persons exposed to formaldehyde has increased the overall weight of the evidence. Based on this new information, an expert working group has determined that there is now sufficient evidence that formaldehyde causes nasopharyngeal cancer in humans, a rare cancer in developed countries. The move follows protracted arguments between the chemical industry – which played down the link – and health advocates, who argued the commonly used industrial chemical should be subject to stringent controls.

IARC working group, 2-9 June 2004. IARC news release, 15 June 2004.