Dimethylaminopropyl chloride, hydrochloride is used primarily as an industrial and research organic chemical intermediate acting as an alkylating reagent in Grignard and other types of reactions. It is also used as a pharmaceutical intermediate for the synthesis of many types of drugs, as an agricultural chemical intermediate, as a photographic chemical intermediate, and as a biochemical reagent for enzyme and other studies. Human occupational or other accidental exposure can occur by inhalation, ingestion, or skin absorption. Male and female F344/N rats and B6C3F1 mice received dimethylaminopropyl chloride, hydrochloride (greater than 99% pure) in water by gavage for 2 weeks or 3 months. Genetic toxicology studies were conducted in Salmonella typhimurium and mouse peripheral blood erythrocytes. In the 2-week toxicity studies, groups of five male and five female F344/N rats and B6C3F1 mice were administered doses of 0, 6.25, 12.5, 25, 50, or 100 mg dimethylaminopropyl chloride, hydrochloride/kg body weight in deionized water by gavage, 5 days per week for 16 days. All dosed male and female rats and mice survived until the end of the 2-week study; one vehicle control female mouse died early. Mean body weights of all dosed groups of rats and mice were similar to those of the vehicle control groups. No gross or microscopic lesions were considered related to dimethylaminopropyl chloride, hydrochloride administration. In the 3-month toxicity studies, groups of 10 male and 10 female F344/N rats and B6C3F1 mice were administered doses of 0, 6.25, 12.5, 25, 50, or 100 mg/kg in deionized water by gavage, 5 days per week for 3 months. One male rat in the 50 mg/kg group died during week 12 of the study, and one female mouse in the 100 mg/kg group died during week 9 and another during week 13. The final mean body weights of 50 mg/kg male rats and 50 mg/kg female mice were significantly less than those of the vehicle controls. Possible chemical-related clinical findings in rats included lethargy in one 50 mg/kg male and one 100 mg/kg male, tremors in one 100 mg/kg male, and ataxia in one 50 mg/kg male and two 100 mg/kg males. Absolute lung weights in the 25, 50, and 100 mg/kg groups of female mice were significantly less than those of the vehicle controls. Total serum bile acid concentrations were increased in 50 mg/kg male rats and 100 mg/kg male and female rats. The incidence of goblet cell hypertrophy of the nose was significantly increased in 100 mg/kg male rats compared to the vehicle controls. There were no significant histopathologic findings in mice. Dimethylaminopropyl chloride, hydrochloride was mutagenic in the Salmonella typhimurium base substitution strains TA100 and TA1535, with and without hamster or rat liver S9 activation enzymes; no mutagenic activity was seen in TA97 or TA98. No increase in the frequency of micronucleated erythrocytes was seen in peripheral blood of male or female mice administered dimethylaminopropyl chloride, hydrochloride for 3 months by gavage. In summary, dimethylaminopropyl chloride, hydrochloride caused increased incidences of goblet cell hypertrophy in the nose of male rats and increased serum bile acid concentrations in male and female rats. In mice, dimethylaminopropyl chloride, hydrochloride caused deaths in females administered 100 mg/kg. The estimated no-observed-effect levels were 50 mg/kg per day for male rats and female mice, 100 to 200 mg/kg per day for female rats, and greater than 100 mg/kg per day for male mice. Synonyms: 3-Chloropropyldimethyl-ammonium chloride; (3-chloropropyl)dimethylamine, hydrochloride; N-(3-chloropropyl)-N,N-dimethylammonium chloride; 3-dimethylamino-1-propyl chloride hydrochloride; 3-dimethylaminopropyl chloride hydrochloride; DMPC; 1-propylamine, 3-chloro-N,N-dimethyl-, hydrochloride.