The EPA is proposing to approve a Tribal implementation plan (TIP) submitted by the Swinomish Indian Tribal Community (SITC or the Tribe). The TIP was submitted to the EPA on June 28, 2012, and supplementary submittals were received on September 24, 2013, November 18, 2013, and January 28, 2014. The TIP establishes regulations for open burning that will apply to all persons within the exterior boundaries of the Swinomish Reservation (the Reservation). The EPA approved the SITC for treatment in the same manner as a State (TAS) to regulate open burning on the Swinomish Reservation under the Clean Air Act (CAA or the Act) on February 16, 2010. This action proposes to federally approve the TIP. If the EPA finalizes this approval, the provisions of the TIP would become federally enforceable. Upon the effective date of a final action to approve the TIP, the SITC's open burning TIP would replace the Federal Implementation Plan (FIP) provisions regulating open burning within the exterior boundaries of the Swinomish Reservation.