| Agent Name |
Benzene |
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| CAS Number |
71-43-2 |
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| Formula |
C6-H6 |
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| Major Category |
Solvents |
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| Synonyms |
(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 |
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| Category |
Aromatic Solvents |
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| Description |
Colorless to light-yellow liquid with an aromatic odor. Note: A solid below 42 degrees F; [NIOSH] |
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| Sources/Uses |
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] |
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| Comments |
"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] 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. [Am J Ind Med 2000;38(1):1-7] In high-dose animal reproductive studies, benzene increases sperm abnormalities, fetal loss, and delayed ossification. [Frazier] |
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| Restricted |
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] |
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| Reference Link |
OSHA Technical Links: Benzene |
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| Exposure Assessment |
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| BEI |
S-phenylmercapturic acid in urine = 25 ug/g creatinine; t,t-Muconic acid in urine = 500 ug/g creatinine; sample at end of shift; |
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| Skin Designation (ACGIH) |
Yes |
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| TLV (ACGIH) |
0.5 ppm |
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| STEL (ACGIH) |
2.5 ppm |
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| PEL (OSHA) |
1 ppm, STEL(OSHA) = 5 ppm (see CFR 1910.1028) |
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| IDLH (NIOSH) |
500 ppm |
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| 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]. |
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| Vapor Pressure |
94.8 mm Hg |
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| Odor Threshold Low |
34 ppm |
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| Odor Threshold High |
119 ppm |
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| Lethal Concentration |
LC50 (rats) = 10,000 ppm/7h |
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| Explanatory Notes |
Detection odor thresholds from AIHA; Flash point = 12 deg F; |
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| Half Life |
Whole body: 9-24 hours; however, up to 90 hours due to distribution in fat; [TDR, p. 154] |
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| Reference Link |
ATSDR Medical Management - Benzene |
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| Flammability (NFPA) |
3: may ignite at ambient temperature |
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| Adverse Effects |
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| Anemia |
Anemia, Aplastic |
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| Neurotoxin |
CNS Solvent Syndrome |
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| Reproductive Toxin |
Yes |
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| IARC Carcinogen |
Known Carcinogen |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: BENZENE
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