International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 3)

For definition of Groups, see Preamble Evaluation.

VOL.: 47 (1989) (p. 43)

5. Summary of Data Reported and Evaluation

5.1 Exposure

Petroleum solvents are hydrocarbon mixtures which can be grouped into three broad categories on the basis of their boiling ranges and solvent strengths, as follows: special boiling range solvents, boiling range, 30-160 oC; white spirits, 130-220 oC; and high-boiling aromatic solvents, 160-300 oC. Within these broad solvent categories, individual solvents (typically boiling within narrower ranges of 15-30 oC) are composed of aliphatic, alicyclic and aromatic hydrocarbons in varying amounts, depending on refining process and end use. Although the content of benzene in petroleum solvents is now generally less than 1% in nonhydrogenated special boiling range solvents and less than 0.1% in other solvents, higher amounts were commonly present in the past.

Exposure to petroleum solvents is widespread in many occupations, including painting, printing, use of adhesives, rubber processing and degreasing. High exposure levels have been measured in many of these occupational environments.

5.2 Experimental carcinogenicity data

A single study in rats exposed by inhalation to a high-boiling aromatic solvent was of insufficient duration to allow an evaluation of carcinogenicity.

5.3 Human carcinogenicity data

In a single case-control study of cancer at many sites, potential long, high exposure to 'mineral spirits' was associated with increased risks for squamous-cell lung cancer and prostatic cancer. In two case-control studies, one of primary liver cancer and one of Hodgkin's disease, an association with organic solvents, including white spirits, was seen. The results of these studies could not be evaluated with regard to petroleum solvents themselves.

5.4 Other relevant data

In humans, petroleum solvents cause nonallergic contact dermatitis and adverse effects on the central nervous system.

In experimental animals, samples of petroleum solvents with a high aromatic content had greater acute toxicity and were more irritating than those that were virtually aromatic-free. A special boiling range solvent containing n-hexane induced chronic toxicity in the peripheral nervous system of experimental animals.

In two studies of malformations in the children of women who had been exposed to petroleum solvents during the first trimester of pregnancy, the numbers of cases were small and the mothers had also been exposed to other substances.

A rubber solvent (special boiling range solvent) induced chromosomal aberrations but not sister chromatid exchange in cultured human cells. Another special boiling range solvent did not induce chromosomal aberrations in cultured mammalian cells, gene conversion in yeast or mutation in bacteria. A sample of white spirits did not induce chromosomal aberrations in mice in vivo, sister chromatid exchange in human cells or mutation in bacteria.

5.5 Evaluation

There is inadequate evidence for the carcinogenicity of petroleum solvents in humans.

There is inadequate evidence for the carcinogenicity of high-boiling aromatic solvents in experimental animals.

No data were available on the carcinogenicity of special boiling range solvents or white spirits in experimental animals.

Overall evaluation

Petroleum solvents are not classifiable as to their carcinogenicity to humans (Group 3).

For definition of the italicized terms, see Preamble Evaluation.


Special boiling-range solvents

White spirits

High-boiling aromatic solvents

Last updated 01/20/98

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       Toxicological Abbreviations