Severity index (S) | LD50 | LC50 | TLV (TWA/STEL/C) |
5 (Other) | Specific effects on human health: carcinogenic, mutagenic or toxic to reproduction. | ||
4 (Very toxic) | LD50 ≤ 50 mg/L (skin) LD50 ≤ 25 mg/kg (ingestion/body weight) | Aerosols or particulates (rats): LC50 ≤ 0.25 mg/liter/4 h Gases and vapors: LC50 ≤ 0.5 mg/liter/4 h | TLV ≤ 3 mg/m3 |
3 (Toxic) | 50 < LD50 ≤ 400 mg/kg or mg/L (skin) 25 < LD50 ≤ 200 mg/kg (ingestion/body weight) | Aerosols or particulates (rats): 0.25 < LC50 ≤ 1 mg/liter/4 h Gases and vapors (rats): 0.5 < LC50 ≤ 2 mg/liter/4 h | 3 < TLV ≤ 9 mg/m3 |
2 (Harmful) | 400 < LD50 ≤ 2000 mg/kg or mg/L (skin) 200 < LD50 ≤ 2000 mg/kg (ingestion/body weight) | Aerosols or particulates (rats): 1 < LC50 ≤ 5 mg/liter/4 h b) Gases and vapors (rats): 2 < LC50 ≤ 20 mg/liter/4 h | 9 < TLV ≤ 50 mg/m3 |
1 (Not classified) | Rats or rabbits: LD50 > 2000 mg/kg (body weight) or mg/L (skin) Rats: LD50 > 2000 mg/kg (ingestion/body weight) | Aerosols or particulates (rats): LC50 > 5 mg/liter/4 h b) Gases and vapors (rats): LC50 > 20 mg/liter/4 h | TLV > 50 mg/m3 |