Agent Name


CAS Number




Major Category



(6)Annulene; Benzene; Benzin; Benzine; Benzol; Benzol 90; Benzole; Benzolene; Bicarburet of hydrogen; Carbon oil; Coal naphtha; Cyclohexatriene; Mineral naphtha; Motor benzol; Nitration benzene; Phene; Phenyl hydride; Polystream; Pyrobenzol; Pyrobenzole; [ChemIDplus] UN1114


Aromatic Solvents


Colorless to light-yellow liquid with an aromatic odor. Note: A solid below 42 degrees F; [NIOSH]


Benzene was used in the past as a solvent in inks, rubber, lacquers, and paint removers. Today, it is used mainly in closed processes to synthesize organic chemicals. Gasoline in some countries contains a high concentration of benzene (as high as 30%); the U.S. average is 1-3%. Workers who remove or clean underground storage tanks may be exposed to significant levels. [ACGIH] Gasoline in North America now contains about 1% benzene. [AIHAJ 2002;63(2):225-30] The European Union (EU) reduced in 2000 the maximum allowed benzene content in gasoline from 5% to 1% by volume. Mean exposures in the Swedish petroleum industry are well below the Swedish occupational exposure limits. [PMID 28578463]


i. "The final OSHA Benzene standard in 1910.1028 applies to all occupational exposures to benzene except some subsegments of industry where exposures are consistently under the action level (i.e., distribution and sales of fuels, sealed containers and pipelines, coke production, oil and gas drilling and production, natural gas processing, and the percentage exclusion for liquid mixtures);" [NIOSH Pocket Guide Appendix] As an organic solvent, benzene can induce narcosis and anesthesia acutely. After chronic exposure, it can cause aplastic anemia and leukemia. [ACGIH] "Exposure to benzene has been associated with development of a particular type of leukemia called acute myeloid leukemia (AML)." [ATSDR Public Health Statement: Benzene] There is sufficient evidence in humans for the carcinogenicity of benzene. Benzene causes acute myeloid leukaemia/acute non-lymphocytic leukaemia. [IARC Monograph Volume 100F (2012)] The WHO classification of AML includes Acute erythroid leukemia and Acute monocytic leukemia. [] Significant benzene exposure increases the risk of leukemia during the 10 years following exposure. Risk is not related to exposures that occurred greater than 20 years prior to the onset of disease. [PMID 10861761] The highest exposures (mean of 11 ppm) in petroleum refinery workers occur in disconnecting cargo loading hoses, and respiratory protection is required. [PMID 20941467] Workers exposed to products containing <0.1% benzene are not likely to be exposed above the TLV of 0.5 ppm. [PMID 18615290] "Our results confirmed the association between high-level benzene exposures and leukemia risks, and provided further evidence of a threshold effect and relevant exposure window." [PMID 27058483] See "Hospital-Based Case-Control Study of MDS Subtypes and Benzene Exposure in Shanghai." [PMID 28146040] In high-dose animal reproductive studies, benzene increases sperm abnormalities, fetal loss, and delayed ossification. [Frazier]


EPA restricts benzene emission from specific point sources; maximum contaminant level in drinking water is 5 ppb; FDA prohibits the use of benzene in food; [ATSDR Case Studies]

Reference Link

OSHA Technical Links: Benzene

Exposure Assessment

S-phenylmercapturic acid in urine = 25 ug/g creatinine; t,t-Muconic acid in urine = 500 ug/g creatinine; sample at end of shift;

Skin Designation (ACGIH)



0.5 ppm


2.5 ppm


1 ppm, STEL(OSHA) = 5 ppm (see CFR 1910.1028)


500 ppm

Excerpts from Documentation for IDLHs

Other human data: It has been stated that 3,000 ppm is endurable for 0.5 to 1 hour [Flury 1928]. It has also been stated that exposure at 19,000 to 20,000 ppm for 5 to 10 minutes is fatal; exposure at 7,500 ppm for 30 minutes is dangerous; exposure at 1,500 ppm for 60 minutes induces serious symptoms; exposure at 500 ppm for 60 minutes leads to symptoms of illness; exposure at 50 to 150 ppm for 5 hours produces headache, lassitude, and weakness; and exposure at 25 ppm for 8 hours has no effect [Gerarde 1960].

Vapor Pressure

94.8 mm Hg

Odor Threshold Low

34 ppm

Odor Threshold High

119 ppm

Lethal Concentration

LC50 (rat) = 10,000 ppm/7h

Explanatory Notes

Detection odor thresholds from AIHA; Flash point = 12 deg F;

Half Life

Whole body: 9-24 hours; however, up to 90 hours due to distribution in fat; [TDR, p. 154]

Reference Link

ATSDR Medical Management - Benzene

Adverse Effects

Anemia, Aplastic


CNS Solvent Syndrome

Reproductive Toxin


IARC Carcinogen

Known Carcinogen

NTP Carcinogen

Human Carcinogen

ACGIH Carcinogen

Confirmed Human

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information


Chemical Information

Search ChemIDplus

Biomedical References

Search PubMed

Related Information in HazMap

Occupational diseases associated with exposure to this agent:


Industrial Processes with risk of exposure:


Activities with risk of exposure: