Expert Report

Review of the Environmental Protection Agency's Draft IRIS Assessment of Formaldehyde (2011)

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The draft health assessment of formaldehyde from the U.S. Environmental Protection Agency needs substantial revision, says this report from the National Research Council. Exposure to formaldehyde has been linked to a variety of adverse health effects, including leukemia and other types of cancer. Formaldehyde enters the environment from many sources, including power plants, cars, gas and wood stoves, and cigarettes; formaldehyde is also found in some foods and is naturally present in the human body. The U.S. Environmental Protection Agency's draft health assessment was developed for its Integrated Risk Information System and will be used as the basis of risk calculations and regulatory decisions concerning human exposures to formaldehyde. The report finds that the draft assessment was not prepared in a consistent fashion, lacks clear links to an underlying conceptual framework, and does not contain sufficient documentation on methods and criteria for identifying evidence.

Key Messages

  • Although the Environmental Protection Agency (EPA) adequately described the studies that it considered in its draft health assessment, critical evaluations of their strengths and weaknesses were generally deficient, and clear rationales for many conclusions were not provided.
  • In several cases, the National Research Council's authoring committee would not have advanced a particular study or would have advanced other studies to calculate the candidate reference concentrations, which are estimates of lifetime concentrations to which someone could be exposed without appreciable risk of particular adverse health effects.
  • The draft assessment provides sufficient evidence of a causal association between formaldehyde and cancers of the nose, nasal cavity, and nasopharnyx.
  • EPA overstated the evidence to deem formaldehyde neurotoxic. The human data are insufficient to support that determination, and the animal studies considered deviate substantially from testing guidelines and common practice.
  • The totality of the epidemiologic evidence for reproductive and developmental toxicity should be described as "suggestive" rather than "convincing."
  • Although EPA provided an exhaustive description of the studies it analyzed and speculated extensively on possible modes of action, the draft assessment does not adequately support the causal determinations it makes for various leukemias and lymphomas.
  • If the methodologic issues are not addressed, EPA's future assessments may still have the same general and avoidable problems that this report highlights.