SUBCHRONIC REPEATED VAPOR EXPOSURE TOXICITY OF 5-VINYL-2-NORBORNENE

5-Vinyl-2-norbornene (VNB: CAS Number 3048-64-4) is an industrial chemical with a potential for exposure to the vapor. To determine any hazards from repeated exposure to the vapor a subchronic exposure study was conducted in which male and female Sprague Dawley rats were exposed to VNB vapor for 6 hours per day, 5 days per week for 14 weeks at mean concentrations of 0, 5, 25.5, and 152 ppm. Subgroups at 0 and 152 ppm were kept for a 4-week post-exposure recovery period. This study was preceeded by a 9-day repeated vapor study in which male and female rats were exposed to mean concentrations of 50, 147, and 352 ppm. In both the 9-day and subchronic studies there were no significant exposure-related effects with respect to signs, mortality, body weights, serum chemistry, or urinalysis. The only hematological effect was an increase in the mean corpuscular volume and mean corpuscular hemoglobin in male rats of the 147 and 352 ppm groups. There were exposure-related increases in liver weights with the 9-day st...