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EC number: 200-753-7
CAS number: 71-43-2
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 oral LD50 in mL/kg (95% CL)
Young adults: 3.8 (2.9 -4.8)
Older adults : 5.6 (4.0 -7.8)
Acute oral toxicity was determined in groups
of at least 6 rats per age and dose level. Benzene was demonstrated to
be of low acute oral toxicity (LD50 >2000 mg/kg) and does not
warrant classification under Dir 67/548/EEC or GHS
The acute inhalation LC50 of
benzene was determined in groups of 10 or 12 female rats to be 13700 ppm
(43767 mg/m3; 43.7mg/L) with a range of 13050-14380 ppm
(41690-45939 mg/m3). Death appeared to be caused by a
depression of the CNS. These animals had increased lung and liver
weights, lung and liver congestion and an increased number of vacuolated
hepatocytes in the liver.
Benzene is of low acute inhalation toxicity
and does not warrant classification under Dir 67/548/EEC.
The acute dermal LD50 for benzene
was determined in groups of 4 rabbits (abraded skin) or guinea pigs
(abraded back skin or non-abraded abdominal skin) using occlusive
The acute dermal LD50 was >9.4
mL/kg (8260 mg/kg) in each case.
In conclusion, benzene is of low acute
dermal toxicity and does not warrant classification under Dir 67/548/EEC
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)".
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
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.
is of low acute toxicity by the oral, inhalation and dermal routes with
LD50/LC50 values exceeding the doses which would warrant classification
(EC) No 1272/2008 of the European Parliament.
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 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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