The rule also imposes new exhaust restrictions that EPA says will cut pollution from these engines by 40% starting in 2004.
Under the rule, engine makers have until the 2007 model year to start using new emission testing procedures. That is a change from the 2004 deadline EPA proposed earlier.
The agency said it expects to follow this rule with another by the end of the year that requires both cleaner engines and cleaner diesel fuel – and will cut pollution by an additional 90%.
In this rule the agency affirmed that its 1997 emissions standard will stand. That standard requires engine manufacturers to cut nitrogen oxide emissions by about 50%, and reduce hydrocarbon emissions, starting in 2004.
The EPA's decision to extend the deadline triggered an attack from the Clean Air Trust, which awarded its clean air "Villain of the Month" award to six diesel engine companies it says have been trying to wiggle out of the consent decree they signed with EPA and the Justice Department by asking for more time to meet the stricter standards. (See "Engine Manufacturers To Pay $83.4 Million in EPA Fines," 10/28/98)