Regular short-term peak exposure to benzene in the supply chain of petroleum products – Review of exposure and existing industry practices for targeted risk management
Exposures to benzene and benzene-containing products are generally well controlled within industry. However, given the recent findings of a possible association of myelodysplastic syndrome with exposure levels that approach some Short Term Exposure Limits, an evaluation of jobs/tasks across the supply chain for petroleum products, which may be associated with similar exposure levels, was undertaken. Review and summarisation of existing industry practices and control strategies in place for regular short-term peak exposures to benzene may support the formulation of best practices in these areas. In this context, benzene exposure data, from the year 2000 onwards, were collected from Concawe member companies and sector reports, representing primarily the following work areas: refining, road tanker terminals, rail car terminals, and ship terminals. The exposure data were used to characterize tasks with potential short-term, regular, exposure to benzene vapor across the supply chain for petroleum products. For the majority of tasks the 95th percentile of the benzene exposure levels was found to be generally low compared to existing reference values (for example TLV ACGIH, UE L.V or from literature). Only for a limited number of tasks and conditions, i.e. sample collection at road terminals (open system), tank dipping, and handling of hoses at ship terminals (products with high benzene content; >20%) measured exposures may occasionally peak. However, the use of proper respiratory protective equipment, as incorporated in benzene control programs in many member companies and also reflected in the contextual data as provided, will protect these workers against adverse health effects. The collected data was additionally utilized to assess the indicative effect of risk management measures and their effect on the short-term benzene exposure levels. Closed system sampling (refining, products with low benzene content) may reduce the benzene concentration in air by 50-70% in comparison with open sampling. However, data availability is limited and for both conditions, measurements were found below the level of detection. Vapor recovery during top loading may reduce the benzene concentration by 30-70% in comparison with top loading without vapor recovery. For majority of the analysed tasks, air concentrations were below the applied reference values for benzene. Limitations of this study include the limited coverage of identified tasks in the defined work areas, and the lack of contextual data from the collected measurements.