TABLE 3-1 Physical and Chemical Properties of Benzene


Cyclohexatriene, phenyl hydride

CAS registry number


Molecular formula


Molecular weight


Boiling point


Melting point


Flash point

−11°C (closed cup)

Explosive limits


Specific gravity

0.8787 at 15°C/4°C

Vapor pressure

94.8 mm Hg at 25°C


Miscible with alcohol, chloroform, ether, carbon disulfide, carbon tetrachloride, glacial acetic acid, acetone, oils

Conversion factors

1 ppm = 3.19 mg/m3; 1 mg/m3 = 0.31 ppm

Abbreviations: mm Hg, millimeters of mercury; NA, not available or not applicable.

Sources: Budavari et al. 1989; HSDB 2005.

outdoor air in metropolitan areas was estimated to be 0.58 ppb (NCI 2003). However, overall average personal exposure has been estimated to be 4.7 ppb, probably because of passive exposure to cigarette smoke (Wallace 1989). Data have shown that homes with smokers have higher benzene concentrations (median, 3.3 ppb) than homes with no smokers (median, 2.2 ppb) (Wallace 1989). Air from a smoke-filled bar contained benzene at up to 11.3 ppb (Brunnemann et al. 1989). The mainstream-smoke benzene emission factor ranges from 5.9 to 73 µg per cigarette, and the sidestream-smoke factor ranges from 345 to 653 µg per cigarette (ATSDR 2005).

Sources of benzene on submarines include petroleum-derived fuels and lubricants, high-temperature paints, and smoking (Crawl 2003). A few measurements of benzene on submarines have been reported. Holdren et al. (1995) reported the results of air sampling at three locations over 6 h during the missions of two submarines. Depending on the sample-collection method, concentration ranges were 5.3-6.3 ppb and 5.5-6.5 ppb on one submarine and 5.8-10 ppb and 16-34 ppb on the other. Raymer et al. (1994) did not detect benzene in a similar sampling exercise on two other submarines. The committee notes that the results presented by Holdren et al. and Raymer et al. represent one-time sampling events on four submarines. Whether the reported concentrations are representative of the submarine fleet is not known, particularly because few details were provided about the conditions on the submarines when the samples were taken.

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