Two Republican senators want the Justice Department to investigate claims that Environmental Protection Agency officials wrongly pursued a “covert propaganda” campaign to promote the agency’s controversial water regulations. 

In a letter to Attorney General Loretta Lynch, Sens. James Inhofe, R-Okla., and Ben Sasse, R-Neb., asked the DOJ to investigate whether the EPA “knowingly and willfully violated” federal law as part of its Clean Water Rule in 2015.

“Only a thorough and independent investigation can determine whether a crime has occurred,” the senators wrote to Lynch in a letter dated last Thursday, noting the penalty for breaking the law in question runs up to a $5,000 fine and two years in prison.

In December, the nonpartisan Government Accountability Office concluded that EPA social media campaigns on the water rules violated the law -- by spending money on grassroots lobbying, and in a way not authorized by Congress.

But the senators, in their letter, suggested the EPA is doing little about it. 

“Despite the fact that the Government Accountability Office found that they broke federal law by running a covert propaganda campaign to support their sweeping WOTUS (Waters of the United States) rule, the EPA has doubled down on their lawlessness,” Sasse said in a written statement. “It’s time for the Department of Justice to investigate.”

The lawmakers claim the EPA continues to violate the law in question -- the Antideficiency Act, which prohibits officials from spending money not approved by Congress -- and that “only a thorough and independent investigation can determine whether a crime has occurred.” 

The GAO report in December had criticized the EPA for using social media to push the new water regulations. It also said the agency went beyond its legal authority by linking to environmental groups’ websites that asked readers to contact lawmakers on the topic.

The GAO probe began in June after Inhofe first requested the review. The watchdog report faulted the EPA for using the social media site Thunderclap to “correct what it viewed as misinformation.” 

While the government’s use of Thunderclap itself wasn’t illegal, the GAO said the agency crossed the line when it asked supporters to share a pro-EPA message on Twitter and Facebook without attributing it to the government. 

The omission is why the EPA was accused of “covert propaganda.”

Since the GAO’s findings, Sasse and Inhofe claim the EPA has not corrected its actions and continues to break the law. 

“Under the Antideficiency Act, EPA must conduct an internal investigation and identify the persons responsible,” they said in the letter to Lynch. “However, EPA is dismissive of GAO’s legal decision. In fact, even though GAO issued its legal decision on December 14, EPA has not removed from its website the messages that GAO found to be covert propaganda and grass roots lobbying.”

The senators also claim a court brief filed on behalf of the EPA mischaracterizes the GAO’s conclusion as an opinion letter and not a formal legal decision that an Antideficiency Act violation occurred. They claim the EPA administrator must also submit a report to Congress detailing the violation and the amount of taxpayer money spent – something the senators say the EPA has not done. 

The regulations in question sought to clarify which waterways in the U.S. are protected under federal law. While the government cast the changes as a way to give clarity, critics say it expands the EPA’s regulatory reach, even to relatively minor bodies of water.

For its part, the EPA has defended its handling of the water regulation campaign and has said everything it’s done has been legal.

“We appreciate the GAO’s consideration of these matters, but respectfully disagree,” Liz Purchia, an EPA public affairs official, wrote in a blog following the GAO report. “At no point did the EPA encourage the public to contact Congress or any state legislature about the Clean Water Rule. … Plain and simple.”

She also argued that critics were “grasping at anything to distract from and derail our progress.”

Calls to the EPA and DOJ for comment on Monday were not immediately returned. Federal government offices in Washington were closed Monday following the weekend’s historic winter storm.