by Anne Hedges

When Congress passed the Clean Air Act Amendments of 1970, it included a provision that required the U.S. Environmental Protection Agency (EPA) to limit hazardous air pollutants from large industrial plants. When it revised the Clean Air Act in 1977, Congress directed the EPA to restore visibility in national parks and wilderness areas by reducing harmful air pollutants such as particulates, sulfur dioxide and nitrogen oxides from large industrial polluters. EPA slow-walked implementation of both programs, failing to adopt rules to reduce haze-forming pollutants until 1999 and forcing Congress to strengthen hazardous air pollution rules in 1990.

This history makes it all the more baffling that companies such as NorthWestern Energy whine that they are being treated unfairly and need more time to reduce lead, arsenic, and other harmful air pollutants that make people sick and harm the environment. It is clear that no amount of time will be enough for NorthWestern since it has been 27 years since adoption of rules requiring reduction in haze forming pollution and 26 years since EPA determined that it was appropriate and necessary to reduce toxic air pollution from coal plants such as the Colstrip plant.

It’s not as if Colstrip has modern day air pollution controls. Just like an old car, the 1980s vintage Colstrip plant relies on outdated air pollution control technology and frequently breaks down when it is most needed. It has the highest rate of toxic air pollution emissions in the nation, releasing millions of tons of harmful air pollution for hundreds of miles downwind every year. Despite this, on February 20, EPA eliminated the most recent Mercury and Air Toxics Standard (MATS) that required the Colstrip plant to decrease toxic air pollution by 50%, to a level that nearly every other plant in the nation already meets.

EPA did something similar regarding regional haze. In December 2025, the EPA approved the Montana Department of Environmental Quality’s plan that requires no pollution reduction at any industrial operation in the state, including the highly polluting Colstrip plant. This means it will be another decade before EPA could require haze reducing pollution controls at large industrial pollution sources such as the Colstrip plant.

Thanks to the legal expertise of Earthjustice, MEIC is challenging the regional haze decision in federal court. We filed the challenge in January 2026 along with the Sierra Club and National Parks Conservation Association. We also are working with Earthjustice and other partners across the country to prevent EPA’s backtracking on MATS.

EPA to Disregard Health Impacts in Economic Analyses

In January, the U.S. Environmental Protection Agency eliminated the need for it to consider harm to human health in its economic analyses of air pollution rules. It will no longer consider lost lives or the cost to the public from such things as increased cancer risk or cardiovascular diseases from air pollution. Instead, EPA will put both thumbs on the scale and only consider the economic harm reducing air pollution might have on businesses.

This one-sided analysis is how EPA will justify decisions to allow increases in air pollutants such as mercury, arsenic, lead, greenhouse gases, volatile organic compounds, particulates, SO2, and so much more. Needless to say, air pollution will increase and the public will suffer the consequences while companies like NorthWestern Energy are allowed to poison downwind communities to increase shareholder profits.