Retrofit/Rebuild Requirements for 1993 and Earlier Model Year Urban Buses; Status of Equipment Certified and Emissions Levels to be Used by Operators Using Compliance Option 2

In an amendment (63 FR 14626, March 26, 1998) to the rule regarding retrofit/rebuild requirements for 1993 and earlier model year urban buses, EPA stated that it would review retrofit/rebuild equipment that was certified by July 1, 1998 and publish the post-rebuild particulate matter (PM) emission levels for urban bus engines affected by the program. Post-rebuild levels are used by operators for calculating target emission levels of their fleets under compliance Option 2. Today's Federal Register document fulfills EPA's obligation to review equipment certified by July 1, 1998, and to publish the post- rebuild PM levels.