The assessment also noted that diesel exhaust causes respiratory problems such as asthma.
"This will underscore that diesel exhaust is a health hazard and should be controlled," said Frank O'Donnell at the Clean Air Trust.
The report is expected to support EPA's push to reduce tail pipe exhaust emissions from buses and trucks by as much as 95 percent by requiring cleaner-burning engine and diesel fuel with ultra-low sulfur content. Last month, EPA rebuffed attempts by some diesel engine manufacturers to postpone the requirements, approving new penalties against manufacturers who fail to meet an October deadline for making cleaner-burning truck engines.
The engine rule does not affect emissions from trucks already on the road, although the separate regulation cutting the amount of sulfur in diesel fuel is expected to produce pollution reductions.
The assessment, based on exposure from diesel engines built prior to the mid-1990s, also evaluates the exposure-response characteristics of the key health effects so that information is available for understanding the possible impact on an exposed population.
The EPA exhaust emission standards for heavy-duty highway engines will become effective with the 2007 model year.
EPA is attacking diesel exhaust on several levels. EPA's Voluntary Diesel Retrofit Program helps state and local agencies to retrofit older engines to make them run cleaner and to develop model programs to reduce emissions from idling engines. The agency is also developing a proposal to address pollution from diesel-powered non-road vehicles and equipment.
The assessment is available on EPA's Web site at cfpub.epa.gov/ncea.