The Environmental Protection Agency may be threatening grid reliability through its regulations by forcing power plants to shut down, according to Republican members of the House Energy and Commerce Committee.

“We are concerned that EPA actions threaten to accelerate fossil generation retirements at the very same time electric system operators report growing shortfalls in such baseload capacity will accelerate blackout risks,” Rep. Cathy McMorris Rodgers, R-Wash., ranking member, and 25 other committee members said in a Tuesday letter to EPA Administrator Michael Regan.

Citing North American Electric Reliability Corp. warnings, the lawmakers said large swaths of the United States face heightened risks of rolling blackouts this summer.

At the same time, the EPA is developing regulations such as the Interstate Transport Rule that could affect fossil-fueled power plants, the Republicans noted.

The lawmakers asked Regan to respond to a series of questions by July 26, including what steps he is taking to address any emergencies on the bulk power system this summer.

The Republicans want more information on the EPA’s so-called “electric generating unit” strategy of using multiple regulations to support the Biden administration’s greenhouse gas reduction goals.

They also want to know what grid reliability waivers of EPA regulations or other emergency actions the agency has taken in the last two years or is considering this summer.

They asked Regan to describe the interactions the EPA has had with the Federal Energy Regulatory Commission, states, and regional grid operators related to proposed regulations.

The Republican members sent similar letters last month to FERC Chairman Richard Glick and Department of Energy Secretary Jennifer Granholm.