Proposed rule · 2026-03072

Partial Approval and Partial Disapproval of Air Quality Implementation Plans; Hawaii; Regional Haze State Implementation Plan for the Second Implementation Period

The Environmental Protection Agency (EPA) is proposing to partially approve and partially disapprove the regional haze state implementation plan (SIP) revision submitted by Hawaii on August 2, 2024, under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. Hawaii's SIP submission is intended to address the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is proposing to approve the portions of Hawaii's submission relating to calculations of baseline, current, and natural visibility conditions, progress to date, the uniform rate of progress, reasonably attributable visibility impairment, progress report requirements, and monitoring strategy and other implementation plan requirements. The EPA is proposing to disapprove the long-term strategy, including the enforceable shutdown of several electric generating units at facilities on the islands of Hawaii and Maui. Additionally, we are proposing to disapprove the portions of the submission relating to reasonable progress goals and FLM consultation requirements.