Regional Haze Rule Rollback

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Shenandoah Valley on hazy and clear days.

Why It Matters

Haze occurs when small particles of air pollution scatter and absorb sunlight, blurring scenic views and decreasing the distance that can be seen from overlooks. In response to this problem, Congress enacted Section 169A of the Clean Air Act to protect visibility in national parks and wilderness areas. The Environmental Protection Agency (EPA) subsequently promulgated the Regional Haze Rule in 1999. The program directs states to implement pollution control plans to improve visibility and air quality at national parks, such as the Grand Canyon. Since the implementation of the regional haze program, the average visual range has increased from 90 to 120 miles in some western parks and from 50 to 70 miles in some eastern parks.

In addition to the benefits for visitors at national parks, the regional haze program delivers public health benefits. The primary pollutants that cause regional haze, including particulate matter,  nitrogen oxides (NOx), sulfur dioxide (SO2), and volatile organic compounds (VOCs), are linked to serious health effects including premature death. Some of these pollutants also contribute to acid rain. Implementation of the Regional Haze Rule and associated regulations has produced sharp declines in the emissions of those pollutants, resulting in improved air quality as well as improved visibility in scenic areas. In fact, EPA estimates that during the first implementation period (2007-2018), there was a reduction in SO2 emissions of 500,000 tons per year and in NOx emissions of 300,000 tons per year.

Current Status

EPA is reviewing certain aspects of a final rule promulgated in 2016 that is intended to ensure that states continue to make progress towards long-term visibility goals. Litigation challenging the final rule is pending in the U.S. Court of Appeals for the D.C. Circuit and has been held in abeyance while EPA completes its review.

On April 12, 2018, President Trump directed the Administrator of EPA, Scott Pruitt, to review EPA’s engagement with states as part of the regional haze program.

EPA is also involved in ongoing litigation regarding the adequacy of multiple state plans. For more information on these lawsuits, visit the post on the Regional Haze State Implementation Plans.

Overview of the Regional Haze Program

The Regional Haze Rule requires that states develop and implement comprehensive plans to reduce human-caused regional haze in designated areas. States also must calculate and work towards interim, short-term progress goals, with a long-term goal of returning targeted areas to their natural visibility conditions by 2064. States have an obligation to consult with the relevant federal land managers during the plan development process – which could include the National Park Service, the U.S. Forest Service, the Bureau of Land Management, and others.

Substantively, the Clean Air Act and the Regional Haze Rule mandate that certain older polluting facilities, like power plants, adopt pollution abatement technology that is determined to be the “Best Available Retrofit Technology.” Similarly, if a federal land manager certifies that visibility impairment is reasonably attributed to a specific facility’s emissions, the state is required to assess the facility and determine whether it should install and operate Best Available Retrofit Technology.

The first state plans were due in 2007. Progress reports are required every 5 years and plan revisions are required every decade, with the first full revision originally due by 2018. If states fail to submit a satisfactory plan, EPA is required to develop a federal plan for the state.

Separate from the Regional Haze program, other Clean Air Act programs aim to curb the interstate air pollution that can lead to visibility concerns.  One key program is the Cross-State Air Pollution Rule (CSAPR), which is an interstate emissions trading program that regulates SO2 and NOx emissions from power plants across a large portion of the country to prevent pollution in one state from adversely affecting air quality in another state.


On May 30, 2012, EPA issued a rule allowing states to include certain older power plants that emit haze-causing pollutants in a state’s CSAPR plan. If the state chooses to regulate the facility under CSAPR, the facility would meet its requirements under the Regional Haze Rule and thus not need to install Best Available Retrofit Technology pollution controls. There is ongoing litigation regarding the legality of this final rule, Utility Air Regulatory Group v. EPA, No. 12-1342. Oral argument was held in the U.S. Court of Appeals for the D.C. Circuit on November 16, 2017.

On May 4, 2016, EPA issued a separate proposed rule to strengthen the Regional Haze Rule by updating and amending the requirements for state plans, Protection of Visibility: Amendments to Requirements for State Plans. After an extension to the comment period, comments were due on August 10, 2016.

On December 14, 2016, EPA issued a final rule with an effective date was of January 10, 2017. The rule included a number of significant technical, measurement, and definitional changes to the Regional Haze Rule. It also included a proposal to enhance the federal land manager consultation requirements and to better integrate states’ long-term and reasonable progress goals for visibility. The rule extended the next deadline for state implementation plans from 2018 to July 31, 2021.

On January 18, 2017, the State of Texas petitioned the U.S. Court of Appeals for the D.C. Circuit to review the December 14, 2016 final rule, Docket No. 17-1021.

Trump Era

On February 22, 2017, the National Parks Conservation Association and the Sierra Club moved to intervene in Texas’ case on behalf of EPA.

On March 10, 2017, the State of Alaska, the Utility Air Regulatory Group (UARG), and the Chamber of Commerce filed separate petitions for review of the final rule, Docket Nos. 17-1074, 17-1075, 17-1076 respectively.

On March 13, 2017, the State of North Dakota, Docket No. 17-1080, The State of Arkansas, Docket No. 17-1079, National Parks Conservation Association and a coalition of environmental groups, Docket No. 17-1078, as well as four additional industry representatives, Docket Nos. 17-1077, 17-1082, 17-1083, 17-1084, filed petitions for review. Additionally, industry groups and UARG sent letters to EPA directly, petitioning the agency to reconsider the rule.

On March 15, 2017, the court consolidated the eleven cases as State of Texas, et al v. EPA, et al, Docket No. 17-1021.

On March 24, 2017, the State of Alaska petitioned EPA to reconsider and stay the rule, citing provisions regarding the impact of international air emissions on states’ visibility goals.

On April 12, 2017, UARG filed a motion to intervene on behalf of EPA in the environmental groups’ challenge to the rule, Docket No. 17-1078, consolidated with No. 17-1021.

On May 16, 2017, EPA filed an unopposed motion to delay the case. EPA filed, and the court granted, similar motions on July 18, 2017, September 15, 2017, and December 15, 2017.

On January 17, 2018, EPA responded to the three petition letters and announced its decision to review the final rule, including the federal land manager consultation requirements and the provisions related to the determination that regional haze is reasonably attributed to a particular source. EPA also announced that it plans to finalize additional guidance documents for the state plans that are due in 2021.

On January 19, 2018, EPA filed a motion to hold the case in abeyance pending its review of the final rule. Environmental groups supported this motion.

On January 30, 2018, the court granted EPA’s motion to hold the case in abeyance.

Thank you to Harvard student Laura Bloomer, JD/MPP 2019 for her assistance with this rule.

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