Vinyl chloride: its impact on occupational medicine practice in Iran.

Upon the establishment of a positive relationship between occupational exposure to VCM and angiosarcoma of the liver, strict precautionary measures for the protection of VCM exposed employees in the Abadan Petrochemical Company have been instituted. All such workers have been required to have pre-employment and annual medical examinations with emphasis on liver functions. Among 43 such employees who have undergone regular medical evaluation in the past three years, no instance of liver dysfunction of angiosarcoma has been discovered. The Iranian Standards Institute reviewing occupational health data and local conditions provisionally set in 1976 a TLV of VCM of 25 ppm TWA for 8 hours with revision foreseen for 1977. It is believed that such precautionary measures should be revised and improved according to available data and knowledge and that variations in other environmental and local factors which may well play an important role in the potential pathogenicity of the exposure should be carefully considered in determining the extent of the precautionary measures and standards in each locality.