US EPA

This risk assessment of 1,3-butadiene, a gas used commercially in the production of various resins and plastics, concludes that 1,3-butadiene is a known human carcinogen, based on three types of evidence: 1) excess leukemias in workers occupationally exposed to 1,3-butadiene (by inhalation), 2) occurrence of a variety of tumors in mice and rats by inhalation, and 3) evidence in animals and humans that 1,3-butadiene is metabolized into genotoxic metabolites.

The best estimate of human lifetime extra cancer risk from chronic exposure to 1,3-butadiene is 9 X 10-3 per ppm based on a linear extrapolation of the increased leukemia risks observed in occupationally exposed workers. The corresponding estimate of the chronic exposure level of 1,3-butadiene resulting in an extra cancer risk of 10-6 (i.e., one in a million) is 0.1 ppb.

1,3-Butadiene also causes a variety of reproductive and developmental effects in mice and rats; no human data on these effects are available. There are insufficient data from which to draw any conclusions on potentially sensitive subpopulations.

Koppikar, A. Health Assessment Document for 1,3-Butadiene (External Review Draft). U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Washington Office, Washington, DC, NCEA-W-0267, 1998.

This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

• Health Risk Assessment of 1,3, Butadiene (External Review Draft) (PDF)  (312 pp, 1 MB, about PDF)

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• Health Assessment of 1,3-Butadiene