The Montana Board of Environmental Review Board has made a landmark decision to require best available control technology to limit pollution from very fine particulate matter called PM2.5.  In a 6-1 vote, the seven-member board declared invalid an air permit for the proposed Highwood Generating Station, a 250-MW coal-fired power plant, because the plant had failed to identify top control technologies to reduce emissions of PM2.5.  

PM2.5 is made up if small particles that lodge deep into the lungs. Even short-term exposures to PM2.5 can cause serious respiratory illnesses including asthma, heart attacks, and even premature death. Based on the severe public health threat posed by PM2.5, EPA made air quality standards for PM2.5 nearly twice as stringent in 2006. However, EPA has not required polluting facilities to install state-of-the-art pollution controls for PM2.5.

Montana is the first state to reject EPA guidance and require a coal plant to achieve maximum reductions in PM2.5 emissions. Conservation groups, who challenged the air permit, hailed the decision. “This is a huge victory for public health,” said Anne Hedges, Program Director of Montana Environmental Information Center. 

According to Earthjustice attorney Abigail Dillen, who represented Montana Environmental Information Center and Citizens for Clean Energy, the Clean Air Act requires installation of state-of-the-art pollution controls for PM2.5. “EPA has been foot-dragging with the knowledge that PM2.5 is making people very sick. We are thrilled that the State of Montana is taking the initiative to protect the air we breathe as the Clean Air Act requires.”

The state’s decision comes as a major blow to the proposed Highwood plant, which has already been denied federal loan funding from the USDA’s Rural Utilities Service. It also creates a legal  precedent with significant implications for other coal plants and industrial facilities across the country. “Montana’s example is going to make it harder to build dirty plants across the country,” said Dillen.

In addition to harmful particulates, Highwood would emit the equivalent of 2.8-million tons of greenhouse gases, including 2.1-million tons of CO2 each year. The plant is proposed for construction on top of a National Historic Landmark outside of Great Falls, Montana.