A conservative think tank filed a lawsuit Thursday to stop the Environmental Protection Agency from destroying text messages to avoid publicly releasing them in response to Freedom of Information Act requests.

The Competitive Enterprise Institute filed the lawsuit with the U.S. District Court for the District of Columbia after repeatedly being told the EPA didn't have records of text messages sent by former EPA Administrator Lisa Jackson and current Administrator Gina McCarthy even though CEI had evidence that the texts were sent.

"Defendant EPA has not provided any of the records responsive to either FOIA request. Instead, it has destroyed them, as part of a policy and practice of destroying such records, in violation of the FRA (Federal Records Act) and FOIA; as a result, it has been unable to locate any such texts in response to plaintiff’s FOIA requests," CEI said in its complaint.

CEI filed FOIA requests for texts sent by McCarthy on the days she testified before Congress. The think tank also requested copies of texts to and from Jackson on a specific day that email records from her "Richard Windsor" alias official email account showed she had a text conversation about a green job opportunity for a company whose CEO she met at a climate rally. The EPA claimed that no such records exist.

According to an email from an EPA official, the texts didn't need to be preserved even though "electronic records" are required by federal law to be saved.

Eric Wachter, director of the EPA Office of the Executive Secretariat, wrote a Sept. 8 email to CEI attorney Christopher Horner saying, “Not all documents created by government employees are subject to preservation under the Federal Records Act. ... The text messages described in the example your provide certainly suggest un-record material not subject to the Federal Records Act.”

According to CEI, the EPA has been purposely destroying the texts. The think tank said it was was "credibly informed" in April that other EPA officials had warned McCarthy, then the assistant administrator for air and radiation, that texts she was sending about congressional oversight efforts during hearings where she was a witness posed a risk to her and the agency.

An Aug. 1 email from Michelle Lo, counsel for EPA, said, “Ms. McCarthy used the texting function on her EPA phone,” but that “none of her texts over the period encompassing the 18 specific dates at issue in CEI’s FOIA request (July 9, 2009, to June 29, 2012) were preserved," according to CEI's complaint.

Horner first exposed Jackson's "Richard Windsor" alias email account last year, and FOIA requests by Horner and CEI related to the Windsor account also revealed Jackson used a personal email address to conduct official business.

Jackson resigned in December, shortly after media reports that the EPA inspector general was investigating whether her use of a private email account for official government business violated transparency laws.

The EPA was ordered by a federal court to release thousands of copies of her emails, which it has done in several batches since January. Many of those released emails, however, are heavily or completely redacted.