Formaldehyde: Assessing the risk

The US Environmental Protection Agency has listed formaldehyde as a priority chemical for regulatory assessment under section 4 (f) of the Toxic Substances Control Act. They will give priority consideration to human formaldehyde exposure in two areas because of the large numbers of people involved: clothing workers who handle textiles treated with formaldehyde-based resins and residents of mobile homes that contain formaldehyde-based resins in construction materials such as foam insulation. Much of the scientific data for determining risks associated with formaldehyde is conflicting and ambiguous, due in part to its presence as a normal metabolite in human biochemistry. Although the chemical induces squamous cell carcinoma in rats, epidemiological studies in occupationally exposed groups show no strong evidence of a causal relationship between formaldehyde and cancer. Dose-response data from an experiment sponsored by the Chemical Industry Institute of Toxicology are used as the primary basis in constructing risk assessments for the human population. The most conservative model and the one chosen by EPA is the linearized multistage model. When the results of this model are examined, most of the groups studied are subject to an unacceptable risk.