Republicans are after federal workers using encryption app Signal to communicate and have sent a letter to the Environmental Protection Agency Inspector General requesting an investigation referencing a Politico report published earlier this month.

The Politico report said a group of federal employees at the EPA were using Signal to discuss what they would do if President Donald Trump’s administration violated the law or deleted vital scientific data.

In the letter sent Feb. 14 to the EPA’s Inspector General, the Chairman of the Science Committee, Rep. Lamar Smith (R-TX) along with Rep. Darin LaHood (R-IL) expressed concern over the off-the-record messages and calls.

“[The] Committee is concerned that these encrypted and off-the-record communication practices, if true, run afoul of federal record-keeping requirements, leaving information that could be responsive to future Freedom of Information Act (FOIA) and congressional requests unattainable," the Republican representatives said.

Conservatives groups have also retaliated against the EPA employees. The right-leaning organization, Cause of Action Institute, submitted a FOIA request seeking the federal workers’ communications using the Signal app. The group’s vice president, Henry Kerner, said the "encrypted app is basically a way to avoid transparency,” Politico reported Wednesday.

EPA employees said they are not using Signal for official government business, and they are concerned of being targeted because they are critical of Trump.

"I don't think anybody can dictate which apps we use on our personal time, for personal conversations," one EPA worker told Politico.

The letter comes after Trump’s administration’s targeting against the EPA. His transition team for the agency is reportedly planning massive cuts at the agency and ending funding for scientific research. His administration also barred the EPA from posting social media updates and speaking to the press.

The inspector general has until Feb. 28 to respond to the letter sent by Republicans.

Meanwhile, Trump’s administration are using the app Confide, which deletes messages once they are read, fearing more leaks to the press, the Washington Post reported this week. Communicating with the Confide app is a threat to transparency and accountability, conservative watchdog Judicial Watch told Politico. The group added the Trump administration is “asking for a lawsuit either Judicial Watch or someone else if they don’t get their act together on these records policies."