A major chemical producer challenged a study raising cancer concerns about occupational exposure to the solvent Dimethylformamide (DMF) – but relied on an internal study it had not published in its defence. DMF has been used widely in laboratories, the manufacture of synthetic textiles and artificial leather, as a solvent for dyes and pigments and in other processes including the production of resins, rubbers and polymers. US researchers, prompted by concerns raised by the Amalgamated Clothing and Textile Workers’ Union, investigated three cases of testicular cancer that had occurred at a leather tannery. All three workers had been involved in dyeing the leather and had worked in the tannery for several years. The authors concluded the cases could be linked to DMF exposure. It followed an earlier study which linked two cases of testicular cancer to DMF exposure. A response to the union-spurred article from US chemical giant DuPont, a major user of DMF, challenged the findings, saying the company’s own study of exposed workers found no excess of testicular cancer. The DuPont study’s findings were unpublished however. The US government’s workplace health research agency, NIOSH, had previously recommended an investigation into the possible cancer causing properties of DMF.

S Levin and others. Testicular cancer in leather tanners exposed to dimethylformamide, The Lancet, volume 330, number 8568, page 1153, 14 November 1987.

JL Chen and GL Kennedy, Dimethylformamide and testicular cancer (reply), The Lancet, page 55, volume 331, numbers 8575-8576, 9 January 1988.

Also see NIOSH September 1990 summary of the studies.