The US Environmental Protection Agency
(EPA) issued the Mobile Source Toxics (MSAT) Rule on February
26, 2007 (40 CFR Parts 59, 80, 85 and 86). This rule
required refiners to reduce the average benzene concentration
in the gasoline pool to 0.62 vol% or less by January 1, 2011.
Refiners producing higher levels could reduce their
concentration by purchasing credits, but they are capped at a
maximum actual average concentration of 1.3 vol%.