An environmental group is demanding radio stations pull ads from a national mining group that blast the administration's coal rules.
The Natural Resources Defense Council (NRDC) claims the National Mining Association's (NMA) ads are "false, misleading, and deceptive."
They are currently running in Arkansas, Colorado, Indiana, Pennsylvania, Virginia and Michigan, where some of the more critical races for Democrats are taking place this year.
The letter to the radio stations also cites a Washington Post fact check, which states the ads are "hyped" and "wholly unsupported."
"We are asking you to immediately cease airing this deceptive ad," the letter states.
The NRDC notes that radio stations have legal obligations under the Federal Communications Commission and are responsible for selecting the material aired on their stations.
"The FCC expects broadcasters to be responsible to the community they serve and act with reasonable care to ensure that advertisements aired on their stations are not false or misleading," according to FCC.
The green group threatens further action if the stations fail to pull the ads.
The NMA has defended its ads, stating that the 80 percent figure refers to a direct comment from Energy Department Deputy Assistant Secretary Julio Friedmann.
During a hearing in February, Friedmann said carbon capture and sequestration technology would increase the wholesale price of electricity by 70 percent to 80 percent.
However, Friedmann later clarified the figure, stating it was in reference to a high lever of carbon capture, not the specific level the EPA proposal would mandate.
The NMA contends that the 80 percent figure is a widely attributed to Friedmann and reported.