The program gives a broad definition to “retrofit,” including retrofitting engines with catalytic converters or diesel particulate filters, engine upgrades, engine replacements, and the use of clean fuels and/or fuel additives. Technologies that are eligible for credits will be determined by a panel of independent experts, engine and emission control manufacturers, and emission test laboratories. A list of approved technologies will be posted on a special EPA website expected to be online within a month.
States that adopt retrofit programs will earn emission credits in their State Implementation Plans. The plans, which must be approved by EPA, outline regulations and other steps each state will take to carry out its responsibilities under the Clean Air Act. EPA says it’s looking for commitments to retrofit 10,000 diesel engines in the first year of the program. Ultimately, the program could affect “hundreds of thousands” of diesel vehicles.