On September 15, 1997, EPA adopted emission guidelines for existing hospital/medical/infectious waste incinerators (HMIWI). Sections 111 and 129 of the Clean Air Act (CAA) require States with existing HMIWI subject to the emission guidelines to submit plans to EPA that implement and enforce the emission guidelines. Indian Tribes may submit, but are not required to submit, Tribal plans to implement and enforce the emission guidelines in Indian country. State plans were due from States with HMIWI subject to the emission guidelines on September 15, 1998. If a State or Tribe with existing HMIWI does not submit an approvable plan within 2 years after promulgation of the emission guidelines (September 15, 1999), sections 111(d) and 129 of the CAA require EPA to develop, implement, and enforce a Federal plan for HMIWI in that State/Tribal jurisdiction. The EPA proposed a Federal plan for HMIWI in the Federal Register on July 6, 1999. This action promulgates the Federal plan to implement emission guidelines for HMIWI located in States and Indian country without effective State or Tribal plans. This Federal plan is an interim action because on the effective date of an approved State/Tribal plan, the Federal plan will no longer apply to HMIWI covered by the State/Tribal plan.