For definition of Groups, see Preamble Evaluation . Summary of Data Reported and Evaluation 5.1 Exposure data Ethylene, the petrochemical manufactured in largest volume worldwide, is produced primarily by the steam-cracking of hydrocarbons.
Few data are available on levels of occupational exposure.
The available data did not allow the Working Group to evaluate the carcinogenicity of ethylene to humans. 5.3 Animal carcinogenicity data Ethylene was tested for carcinogenicity in one experiment in rats exposed by inhalation. No increase in tumour incidence was reported. 5.4 Other relevant data Endogenous but unidentified sources of ethylene exist in man and experimental animals. Exposure to ethylene results in the formation of adducts with proteins.