[Toxicity of 2-mercaptobenzothiazole in mice]

2-mercaptobenzothiazole (MBT) has been used mainly as a vulcanization accelerator in rubber manufacture and an intermediate in the production of other accelerators. Acute and chronic toxicity studies were performed to evaluate its potential to induce toxicological effect using Slc:ddY mice. The oral LD50 values of MBT (mg/kg) were as follows: (1) suspension in 5% gum arabic solution: 1558 for males and 1490 for females. (2) suspension in olive oil: 3148 for males. Convulsion was the major change in general conditions observed. The acute toxicity of MBT in males was stronger when suspended in 5% gum arabic solution than that when suspended in olive oil. A 20-month chronic toxicity study of MBT on mice was carried out with dose levels of 30, 120, 480 and 1920 ppm in the diet. Inhibition of body weight gain was observed in the 1920 ppm group of the males from the initial stage of treatment. Histopathologically, cell infiltration in the interstitium of kidney in the 1920 and 480 ppm groups of the males were found at 20th month. It was concluded that no observable effect level of MBT was 120 ppm (14.6 mg/kg/day for males and 13.52 mg/kg/day for females).