Benzene releases from gasoline stations - Implications for human health: Conclusion and next steps
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Conclusion
In this report, the short-term benzene releases occurring due to tanker truck unloading of gasoline into storage tanks at gasoline stations and long-term releases of benzene from gasoline station total evaporative losses are estimated. For those living in the vicinity of the gasoline station, the incremental risks for tumourogenicity from long-term inhalation exposure to evaporative emissions of benzene from gasoline ranged from 3 to 32 per million population at a distance of 20 m from the gasoline station fenceline. Risk levels of 10 per million and above are of particular concern. The contributions from gasoline station benzene emissions influences exposures up to distances of about 70 to 300 m from the station fenceline, depending on the fuel throughput. The short-term inhalation exposures to emissions of benzene from gasoline unloading by tanker trucks results in MOEs for developmental hemotoxicity effects in pregnant people at 10 m from the gasoline station fenceline that are well below 300, and these MOEs are considered inadequate for protection of human health. At distances up to 210 m to 240 m from the fenceline, the exposure concentrations are still greater than the California EPA AREL for short-term benzene inhalation (OEHHA 2014). There is the potential for these short-term (hourly) exceedances to occur more than 300 times over a year for a high-throughput station, which may result in almost daily elevated periodic exposures. For both types of releases, it is concluded that the inhalation exposures to benzene attributable to gasoline station emissions may pose unacceptable risks to human health for the general population living in the vicinity.
There are methods to reduce benzene exposures and human health risks associated with benzene emissions from gasoline stations. These include vapour recovery and the use of pressure/vacuum (p/v) valves on vent stacks at gasoline stations, and the implementation of minimum setback distances from gasoline stations for new construction. These could contribute to a decrease in benzene exposure for the general population in Canada, including potentially vulnerable populations such as pregnant people, fetuses, and children.
Next steps
The Government of Canada will explore possible risk management options to reduce the release of benzene vapours from gasoline stations, taking into consideration actions at the provincial/territorial level and other federal actions impacting the petroleum sector. Consultations will take place before any potential risk management measures are developed.