The National Toxicology Program conducted a
cancer evaluation on 1 bromopropane for possible listing in the Report on
Carcinogens (RoC). The
cancer evaluation is captured in the RoC monograph, which was peer reviewed in a public forum. The monograph consists of two components: (Part 1) the
cancer evaluation, which reviews the relevant scientific information, assesses its quality, applies the RoC listing criteria to the scientific information, and provides the NTP recommendation for listing status for 1 bromopropane in the RoC, and (Part 2) the substance profile proposed for the RoC, containing the NTP's listing status recommendation, a summary of the scientific evidence considered key to reaching that decision, and data on properties, use, production, exposure, and Federal regulations and guidelines to reduce exposure to
1-bromopropane. This monograph provides an assessment of the available scientific information on 1 bromopropane, including human exposure and properties, disposition and toxicokinetics,
cancer studies in experimental animals, and studies of mechanisms and other related effects, including relevant toxicological effects, genetic toxicology, and mechanisms of carcinogenicity. From this assessment, the NTP recommended that 1 bromopropane be listed as reasonably anticipated to be a human
carcinogen in the RoC based on sufficient evidence from studies in experimental animals, which found inhalation exposure to
1-bromopropane caused skin
tumors in male rats, large intestine
tumors in female and male rats, and lung
tumors in female mice. Also noted was that 1 bromopropane, either directly or via reactive metabolites, caused molecular alterations that typically are associated with
carcinogenesis, including genotoxicity, oxidative stress, and
glutathione depletion. These alterations, observed in mainly in vitro and toxicity studies in rodents, are relevant to possible mechanisms of human carcinogenicity and support the relevance of the
cancer studies in experimental animals to humans.