[Experimental studies on the acute toxicity of tetrahydrofuran in animals]

The toxicity of tetrahydrofuran (THF), an important solvent in chemical industries, was studied by experiments on mice and rats. Acute toxicity was studied by intraperitoneally injecting 20% THF solution in various doses and by causing THF of various concentrations to be inhaled. Toxic symptoms appearing during the experimental period were observed. The results are as follows: 1. Acute toxic dose of THF. LD50 was estimated to be 2,500 mg/kg in mice with intraperitoneal administration of 20% THF-olive oil solution and 1,900 mg/kg in mice and 2,900 mg/kg in rats with intraperitoneal administration of 20% THF-0.9% NaCl solution. LC50 was estimated to be 21,000 ppm in rats when THF was inhaled for three hours. 2. Acute toxicity by inhalation of THF for three ours. Rats exposed to 100 to 200 ppm of THF showed no significant effects, except for slight local irritant symptoms such as redness of the nose and eyelids. Almost all rats exposed to over 5,000 ppm of THF displayed marked local irritant symptoms such as edema or opacity of the cornea, salivation and discharge or bleeding in nasal mucosa. A cataleptoid posture, coma and clonic muscle spasms indicating irritant symptoms of the central nervous system were also observed.