Abstract  This document presents the scope of the risk evaluation to be conducted for 1-BP. If a hazard, exposure, condition of use or potentially exposed or susceptible subpopulation has not been discussed, EPA, at this point in time, is not intending to include it in the scope of the risk evaluation. As per the rulemaking, Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (TSCA), with respect to conditions of use in conducting a risk evaluation under TSCA, EPA will first identify “circumstances” that constitute “conditions of use” for each chemical. While EPA interprets this as largely a factual determination—i.e., EPA is to determine whether a chemical substance is actually involved in one or more of the activities listed in the definition—the determination will inevitably involve the exercise of some discretion.

Abstract  As a replacement for chlorofluorocarbons that cause ozone depletion, 1-bromopropane has been widely used in work place. In the present study, the formation of N-7-guanine adduct in DNA by 1-bromopropane was evaluated in vitro to elucidate the possible mechanism of its toxic action. N-7-Propyl guanine was chemically synthesized and structurally characterized by NMR, UV, HPLC, and liquid chromatographyelectrospray ionization mass spectrometry (LC- ESI MS) for using as a reference standard. An incubation of 2'-deoxyguanosine with 1-bromopropane produced N-7-propyl adduct, which was identified by UV, HPLC and ESI-MS. In addition, N-7-guanine adduct was also identified from the incorporation of calf thymus DNA with 1-bromopropane at the physiological condition by LC-ESI MS. Furthermore, the production of adduct was proportional to the amounts of 1-bromopropane used. These results indicated that the molecular mechanism underlying toxic effects of 1-bromopropane would be associated with the adduct formation on DNA at least in part.