Benzothiazole

Endpoint summary

Description of key information

Benzothiazole was found to be toxic if swallowed, harmful in contact with skin and harmful by inhalation.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

177 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

5 000 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

933 mg/kg bw

Additional information

The acute oral toxicity of benzothiazole was investigated in male and female SPF rats. 6 male and 5 female groups of 10 animals were dosed with 0.1, 0.18, 0.2, 0.23, 0.25, 0.3 mL/kg bw and 0.1, 0.13, 0.15, 0.16, 0.18 mL/kg bw benzothiazole per gavage and observed for 14 days following exposure for mortality and clinical signs. Mortalities occurred at dose levels equal to and exceeding 0.18 mL/kg bw between 8 and 24 hours after administration in male rats and in female rats at dose levels equal to and exceeding 0.13 mL/kg bw between 8 and 24 hours.

Clinical signs like paralysis of the rear extremities, bloody tears, narcosis, prone-/ side position, decreased weight and reduced general condition were observed. The calculated LD50 for male rats was 0.206 mL/kg bw (=258 mg/kg bw) and 0.142 mL/kg bw (=177 mg/kg bw) for female rats

(Loeser, Bayer AG, 1982).

The acute inhalative toxicity of benzothiazole was investigated in study according to OECD guideline 403. Rats were exposed nose/head-only to an atmosphere containing analytical concentrations of 0.377 mg/L (vapour); 2.36 mg/L (aerosol) and 6.154 mg/L (aerosol) benzothiazole for 4 hours. Clinical signs of toxicity were related to dose. Control groups and the 376.5 mg/m³ air groups were without symptoms. Tumbling walk, decreased and increased motility, side-and prone position, decreased and increased respiration, breathing noises, paleness and restricted palpebral fissure were observed at a concentration of 2360.7 mg/m³ air benzothiazole. The clinical signs at 6153.9 mg/m³ air benzothiazole were decreased and increased motility, restricted palpebral fissure, side position, narcotized, complicated respiration, breathing noises, cyanosis, paleness, red noses and lacrimation. Mortalities occurred at 6153.9 mg/m³ air 4 hours after administration.The calculated LC50 was 5000 mg/m³ air (Pauluhn, Bayer AG, 1981).

The acute dermal toxicity of benzothiazole was investigated in 5 male and 5 female rats in a GLP study performed according to guideline study 402.

The animals were dosed with 500, 1000 and 2000 mg/kg body weight benzothiazole. Sedation was observed at dose levels equal to and exceeding 1000 mg/kg body weight. Also chromodakryorrhoe was observed at 1000 mg/kg bw in 3 male rats. Mortalities occurred at dose levels equal to and exceeding 1000 mg/kg bw 1 to 3 days after administration. The calculated LD50 in male rats was 1231 mg/kg body weight and in female rats 933 mg/kg bw (Bomhard, Bayer AG, 1995).

Justification for classification or non-classification

LD50 (oral) = 177 mg/kg bw

Classification:

DSD: T, R25 Harmful if swallowed

GHS: Acute Oral Category 3, H301

LD50 (dermal) = 933 mg/kg bw

Classification:

DSD: Xn, R21 Harmful in contact with skin

GHS: Acute Dermal Category 3, H311

LC50 (inhalation) = 5000 mg/m³

Classification:

DSD: Xn, R20 Harmful by inhalation

GHS: Acute Inhalation Category 4, H332