For definition of Groups, see Preamble Evaluation . Propylene is a major chemical intermediate, produced by catalytic or thermal cracking of hydrocarbons or as a by-product of petroleum refining. It is used mainly in the preparation of alkylates for gasoline and in the production of polypropylene, acrylonitrile, propylene oxide and a number of other industrial chemicals. Propylene is introduced into the atmosphere from natural and man-made sources, including emissions from vegetation, burning of organic material and incomplete combustion of fossil fuels, and from its production and use.
Few data are available on levels of occupational exposure.
No relevant data were available to the Working Group. 5.3 Animal carcinogenicity data Propylene was tested by inhalation in two studies in mice and in two studies in rats. A slight increase in the incidence of vascular tumours was observed in female mice in one study. In one study in rats, no treatment-related increase in tumour incidence was observed. In two studies in mice and rats exposed by inhalation, insufficient information was provided to allow an assessment of carcinogenicity.