NTP-CERHR Expert Panel Report on the reproductive and developmental toxicity of 2-bromopropane

Abstract

The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of the CERHR is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction, including development, caused by agents to which humans may be exposed. 2-Bromopropane (2-BP) was nominated by NIOSH and selected for evaluation by the CERHR based primarily on documented evidence of worker exposures and published evidence of reproductive toxicity in both rodents and humans. In the US, 2-BP is a contaminant (<0.1%) of 1-bromopropane which is used in spray adhesives and as a precision cleaner and degreaser. 2-BP may also be used as an intermediate in the synthesis of pharmaceutical dyes and other organic chemicals. In Asia 2-BP has been used as a replacement for chlorofluorocarbons and 1,1,1-trichloroethane. The evaluation of 2-BP was a 4-month effort by a 9-member panel of academic, private, and government scientists that culminated in a public meeting in December 2001. At that meeting, the expert panel reviewed the scientific evidence on 2-BP and reached conclusions regarding its potential effects on human reproduction. The background information on 2-BP and findings of the expert panel are contained within this report. The Expert Panel Report on 2-bromopropane is intended to (1) interpret the strength of scientific evidence that a given exposure or exposure circumstance may pose a hazard to reproduction and the health and welfare of children; (2) provide objective and scientifically thorough assessments of the scientific evidence that adverse reproductive/developmental health effects are associated with exposure to specific chemicals or classes of chemicals, including descriptions of any uncertainties that would diminish confidence in assessment of risks; and (3) identify knowledge gaps to help establish research and testing priorities. Staff scientists from the CERHR and members of the CERHR Core Committee (oversight committee to the CERHR whose members include NTP participating agencies) have reviewed the report and the CERHR will seek public review and comment through a Federal Register notice. Subsequent to this comment period, the NTP will prepare the NTP-CERHR Report on 2-bromopropane that contains NTP’s conclusions regarding the potential for 2-BP to adversely affect human reproduction. The NTP will base its conclusions on the Expert Panel Report on 2-bromopropane, any public comments received on that report, and any relevant information available since the expert panel meeting. The NTP-CERHR report will include the public comments and the Expert Panel Report as appendices. The NTP-CERHR Report on 2-bromopropane will be made publicly available and transmitted to health and regulatory agencies. The NTP and the CERHR wish to thank the members of the Bromopropanes Expert Panel for their contributions to the evaluation of 2-BP. We greatly appreciate their time, effort, and objectivity during this evaluation process. We also wish to thank the contract staff for their support in convening the expert panel and preparing the Expert Panel Report. The NTP-CERHR is headquartered at NIEHS, Research Triangle Park, NC and is staffed and administered by scientists and support personnel at NIEHS and at Sciences International, Inc., Alexandria, Virginia.