EPA will be holding a
Retrofit Technology Verification Workshop on December 13, 2007 in
Washington, DC. This workshop is intended for technology vendors,
original equipment manufacturers, fuel and fuel additive makers, and
other diesel engine technology organizations interested in an in-depth
review of EPA's retrofit verification process. The conference location
will soon be determined.

http://www.epa.gov/otaq/retrofit/verif-list.htm