TABLE 11-1 Physical and Chemical Properties of Toluene


Methylbenzene; phenylmethane

CAS registry number


Molecular formula


Molecular weight


Boiling point


Melting point


Flash point

4.4°C (closed cup)

Explosive limits


Specific gravity

0.866 at 20°C/4°C

Vapor pressure

28.4 mm Hg at 25°C


Very slightly soluble in water; miscible with alcohol, chloroform, ether, acetone, glacial acetic acid, carbon disulfide

Conversion factors

1 ppm = 3.77 mg/m3; 1 mg/m3 = 0.27 ppm

Abbreviations: NA, not available or not applicable.

Sources: Vapor-pressure data from HSDB 2006; all other data from Budavari et al. 1989.

source of toluene in outdoor air is motor-vehicle emissions; contributors to indoor air concentrations include emissions from household products and cigarette smoke. The toluene emission factor for cigarettes was reported as 80 µg/cigarette (ATSDR 2000).

Sources of toluene in a submarine include paints and coatings (Crawl 2003). The committee notes that cigarette-smoking is also a likely contributor to toluene concentrations in a submarine. Raymer et al. (1994) reported the results of air sampling conducted during the missions of two submarines. The fan room, galley, and engine room in each submarine were sampled over 6 h. Sampling indicated toluene concentrations of 11 ppb in the fan room, 11 ppb in the galley, and 19 ppb in the engine room of one submarine and 14 ppb in the fan room, 14 ppb in the galley, and 27 ppb in the engine room of the other submarine. A similar sampling exercise (two submarines, three locations, and sampling duration of 6 h) was reported by Holdren et al. (1995). Toluene concentrations in one submarine ranged from 122 to 137 ppb and from 241 to 342 ppb, depending on the sampling method, and in the other submarine from 14 to 21 ppb and from 17 to 23 ppb, depending on the sampling method. The committee notes that the results presented by Raymer et al. (1994) and Holdren et al. (1995) represent one-time sampling events in four submarines. Whether the reported concentrations are representative of the submarine fleet is not known, particularly inasmuch as few details were provided about the conditions in the submarines when the samples were taken.

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