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EC number: 271-213-6 | CAS number: 68526-56-7
Benzene does not pose an acute hazard following ingestion (oral LD50 > 2000 mg/kg), skin contact (dermal LD50 > 5000 mg/kg) or acute inhalation (4 hour LC50 >
20 mg/L) exposures.
Acute toxicity oral
An oral LD50 value in rats of > 2000 mg/kg is derived from two studies (Kimura et al, 1971; Withey and Hall, 1975). Although little information on clinical signs is included in these publications the EU RAR (2008) stated "depending on the dose the main clinical signs are sedation and hind-limb paralysis".
Acute toxicity inhalation
Acute inhalation toxicity of benzene is low with a LC50 value of 44.5 mg/L after a 4-hour exposure for rats. Death was reported to be caused by depression of the central nervous system. The main pathological findings were congestion of the lungs and liver (Drew and Fouts 1974).
Acute toxicity dermal
A dermal LD50 value of >8260 mg/kg bw for rabbits and guinea pigs was reported by Roudabush et al. (1965). No information on clinical signs or necropsy information are provided.
Acute toxicity: other route
No information available
The EU RAR (2008) reports "existing data on human accidents demonstrate that ingestion of 15 mL (176 mg/kg bw) benzene can secondarily cause death after collapse, bronchitis and pneumonia due to lung aspiration." "Exposure for 5-10 minutes to benzene vapours of 65-61 mg/L is fatal and exposure to 25 mg/L for 30 minutes is dangerous to life, while a one-hour exposure to 1.6 mg/L causes only some symptoms of illness (Gerarde, 1960)".
Justification for selection of acute toxicity – oral endpoint A consistent oral LD50 value in rats of > 2000 mg/kg is available from two studies. The EU RAR concluded "depending on the dose the main clinical signs are sedation and hind-limb paralysis". Justification for selection of acute toxicity – inhalation endpoint The acute inhalation toxicity of benzene is low with a LC50 of > 20 mg/L in rats following a 4-hour exposure. Death was reported to be caused by CNS depression. Justification for selection of acute toxicity – dermal endpoint The acute dermal LD50 of benzene in rats is >5000 mg/kg bw.
Benzene is of low acute toxicity by the oral, inhalation and dermal routes with LD50/LC50 values exceeding the doses which would warrant classification under Dir 67/548/EEC or Regulation (EC) No 1272/2008 of the European Parliament.
The viscosity of benzene is low (dynamic 0.604 mPa s at 25°C) and is expected to have a surface tension of 33mN/m at 25°C) which justifies classification as harmful and should be labelled Xn, R65, "May cause lung damage if swallowed" under Dir 67/548/EEC and under Regulation (EC) 1272/2008 "Aspiration toxicity Category 1, H304".
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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