Gasoline Mobile Source Air Toxics

The Mobile Source Air Toxics (MSAT) rules reduce hazardous air pollutants, also known as air toxics, emitted by cars and trucks. Air toxics include benzene and other hydrocarbons such as 1,3-butadiene, formaldehyde, acetaldehyde, acrolein, and naphthalene. Each refinery and importer must meet specific compliance baselines for conventional and reformulated gasoline. 

For the MSAT gasoline fuel program, beginning January 1, 2011, refiners must meet an annual average gasoline benzene content standard of 0.62 volume percent (vol%) for all of their gasoline, both reformulated and conventional, nationwide. In addition to the 0.62 vol% standard, refiners must also meet a maximum average benzene standard of 1.3 vol% beginning on July 1, 2012. The national benzene content of gasoline today is about 1.0 vol%. (Gasoline sold in California is not covered because California had already implemented standards similar to those EPA established under the MSAT program.)

The regulations include a nationwide credit averaging, banking, and trading program. A refinery’s or importer’s actual annual average gasoline benzene levels may not exceed a maximum average standard. The program has helped to decrease benzene levels in gasoline throughout the country, with less geographic variability in gasoline benzene levels. Areas where benzene levels were highest, such as Alaska and the Northwest, are expected to achieve the most significant reductions.

Learn more about Mobile Source Air Toxics program.