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

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 54 (1992) (p. 229)

CAS No.: 2973-10-6
Chem. Abstr. Name: Sulfuric acid, bis(1-methylethyl)ester

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Diisopropyl sulfate is an intermediate in the indirect hydration (strong- or weak-acid) process for the preparation of isopropanol from propylene. It has no other known industrial use.

No data were available on levels of occupational exposure to diisopropyl sulfate.

5.2 Human carcinogenicity data

An early US cohort study of isopropanol manufacture using the strong-acid process in a petrochemical plant demonstrated an excess risk for nasal sinus cancer. An increased risk for cancer of the buccal cavity and pharynx was suggested in a cohort of workers at an isopropanol unit in the USA. A cohort study at an isopropanol plant in the United Kingdom indicated an increased risk for nasal cancer (based on one case only) and for brain tumours.

One cohort study at a US isopropanol and ethanol manufacturing plant revealed an increased risk for laryngeal cancer. A subsequent case-control study nested in an expanded cohort at this plant indicated that the increased risk was related to exposure to sulfuric acid; the risk persisted even after exclusion of workers in the ethanol and isopropanol units. A cohort study from a US plant producing ethanol and isopropanol suggested an increased risk for cancers of the larynx, buccal cavity and pharynx, but not of the lung, in strong-acid workers.

No measurement of exposure to diisopropyl sulfate was available for the industrial processes investigated in the epidemiological studies. It is therefore difficult to assess the contribution of diisopropyl sulfate to the increased cancer risks. Furthermore, exposure to mists and vapours from strong inorganic acids, primarily sulfuric acid, probably plays a role.

5.3 Animal carcinogenicity data

Diisopropyl sulfate was tested for carcinogenicity by subcutaneous injection in one strain of rats and by skin application in one strain of mice. It produced local sarcomas in rats skin papillomas and carcinomas in mice. In a screening study in two strains of mice, an increased incidence of lung adenomas was observed following subcutaneous injection.

5.4 Other relevant data

No data were available to the Working Group.

5.5 Evaluation

There is inadequate evidence for the carcinogenicity in humans of diisopropyl sulfate.

There is sufficient evidence for the carcinogenicity in experimental animals of diisopropyl sulfate.

Overall evaluation

Diisopropyl sulfate is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.

Subsequent evaluation: Vol. 71 (1999)


Last updated: 13 April 1999

    See Also:
       Toxicological Abbreviations
       Diisopropyl Sulfate  (IARC Summary & Evaluation, Volume 71, 1999)