Over the past several years, EPA has worked with the marine industry, U.S. Coast Guard, California Air Resources Board, Southwest Research Institute, and others, including several marine engine manufacturers on a series of development and test programs for the use of catalytic exhaust aftertreatment on sterndrive/inboard (SD/I) marine engines. Results from this testing suggest that significant emission reductions can be achieved from SD/I engines through the use of catalysts. According to the EPA, the fresh water durability study has shown that these emission reductions can be achieved over the lifetime of the engine. EPAe anticipate that the salt water testing will show similar results.