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. 1-Bromopropane (1-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 and developmental toxicity in rodents. 1-BP is used in spray adhesives and as a precision cleaner and degreaser. It may also be used as an intermediate in the synthesis of pharmaceuticals, insecticides, quaternary ammonium compounds, flavors, and fragrances and as a solvent for fats, waxes, or resins. The evaluation of 1-BP was a 4-month effort by a 10-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 1-BP and reached conclusions regarding its potential effects on human reproduction and development. The background information on 1-BP and findings of the Expert Panel are contained within this report. Expert Panel reports are 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 monograph on 1-bromopropane that contains its conclusions regarding the potential for 1-BP to adversely affect human reproduction or development. The NTP will base its conclusions on the Expert Panel report on 1-bromopropane, any public comments received on that report, and any relevant information available since the Expert Panel Meeting. The NTP-CERHR monograph will include the public comments and the Expert Panel report as appendices. The NTP-CERHR report on 1-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 1-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. Reports can be obtained from the website ( http://cerhr.niehs.nih.gov) or from: Michael D. Shelby, Ph.D., NIEHS EC-32, P.O. Box 12233, Research Triangle Park, NC 27709, USA. Tel.: +1-919-541-3455; e-mail: shelby@niehs.nih.gov

Highlights

  • Information concerning risk of developmental toxicity associated with exposure to 2-BP is lacking in humans

  • Reproductive effects observed in female rats are similar to those observed in occupationally exposed women

  • Amenorrhea with associated ovarian pathology in selected women has been associated with occupational exposure to 2-BP [3], the inadequate exposure assessment and small sample size limit its use in assessing human health risks

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Summary

Chemical and physical properties

Technical products and impurities Two studies describe the composition of 2-BP that was used at plants in Asia. In a Korean plant, the purity of 2-BP used was 97.4% and contaminants included n-heptane (0.33%), 1,2-dibromopropane (0.2%), and 1,1,1trichloroethane (0.01%) [3,4,5]. The reported purity of 2-BP used in a Chinese plant was 98.08% and contaminants consisted of 2-propanol (1.76%), dibromopropane (0.085%), benzene (0.055%), and trichloroethylene (0.10%) [6]. The composition of the spray adhesive was described as 55% 1-BP, 8% VM&P Naphtha, and 2% ethyl acetate in one case [8]; in another case the spray adhesive contained 60–70% 1-BP [9].

Use and human exposure
Utility of data
Summary of human exposure data
Toxicokinetics
General toxicity
Genetic toxicity
Potentially sensitive subpopulations
Summary of general toxicology and biological effects
Human data
Experimental animal toxicity
Summary of developmental toxicity
X XII I II and III V
Summary of reproductive toxicity
Summary and conclusions of reproductive and developmental hazards
Summary of human exposure
Overall conclusions
Findings
Critical data needs
Full Text
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