No epidemiological studies were available to the Working Group. A small number of cases of, mainly, bronchial carcinoma has been reported. It produced local sarcomas and tumours of the nervous system. Dimethyl sulfate rapidly decomposes on contact with water, as a result of which it very rapidly disappears from the circulation of dosed rats. It is corrosive or irritant to the skin, eyes and respiratory tract of exposed people, and may result in death caused by respiratory failure.
Dimethyl sulfate is embryotoxic to rats and causes malformations among surviving foetuses.
Workers exposed to dimethyl sulfate have developed chromosomal aberrations in their circulating lymphocytes. Dimethyl sulfate has been subjected to a broad range of in-vitro tests for genotoxic activity, in which positive results were consistently found without the need for exogenous metabolic activation systems. It has also consistently produced positive responses in the small number of in-vivo tests to which it has been subjected. It forms a variety of alkylated bases with DNA in vitro and the same alkylated bases are formed in vivo . There is inadequate evidence for the carcinogenicity in humans of dimethyl sulfate.