U.S. Senate candidate and Kentucky Secretary of State Alison Lundergan Grimes (D). (Win McNamee/Getty Images)

A trio of Democratic candidates running in high-profile congressional races in two of the biggest coal-producing states quickly criticized President Obama on Monday over his administration's new proposal to reduce carbon dioxide emissions from coal plants in the next 16 years.

Rep. Nick Rahall (D-W.Va.) not only criticized the "disastrous new rules" but also vowed to introduce legislation to stop them. Rahall faces a tough reelection bid against state Sen. Evan Jenkins (R) in a district where Mitt Romney received nearly twice as many votes as Obama in 2012.

Running in West Virginia's open U.S. Senate race, Secretary of State Natalie Tenannt (D) also panned the proposal.

"I will stand up to President Obama, Gina McCarthy and anyone else who tries to undermine our coal jobs," Tennant said. "Washington bureaucrats need to understand, these are not numbers on a balance sheet, they are real people with families to feed."

The Environmental Protection Agency proposed a regulation Monday to cut carbon dioxide emissions from existing coal plants by up to 30 percent (from 2005 levels) between now and 2030.

West Virginia produced 11 percent of the country's coal in 2013, according to the U.S. Energy Information Administration, more than every other state except Wyoming. The third-biggest coal producer? Kentucky, where Secretary of State Alison Lundergan Grimes (D) is running against Senate Minority Leader Mitch McConnell (R). Grimes also took a swipe at Obama's plan.

"President Obama's new EPA rule is more proof that Washington isn't working for Kentucky," Grimes said in a statement. "Coal keeps the lights on in the Commonwealth, providing a way for thousands of Kentuckians to put food on their tables. When I'm in the U.S. Senate, I will fiercely oppose the president's attack on Kentucky's coal industry because protecting our jobs will be my number one priority."