Environmental Protection Agency Administrator Scott Pruitt, left, attends a briefing on this year's hurricane season at the Federal Emergency Management Agency Headquarters, Wednesday, June 6, 2018, in Washington. (AP/Andrew Harnik)
Washington CNN  — 

The US Office of Special Counsel is investigating whether Environmental Protection Agency aides have been dismissed or demoted as retaliation for questioning EPA Administrator Pruitt’s decisions and spending, two people in contact with the office tell CNN.

Kevin Chmielewski, a former deputy chief of staff to Pruitt, said he was interviewed for almost eight hours on Thursday.

A second person said they have been contacted by investigators but asked not to be named.

The Office of Special Counsel predates and is not related to Justice Department special counsel Robert Mueller.

This investigation review becomes at least the 14th federal probe into Pruitt’s spending and ethics. The EPA inspector general said earlier this year it will also review the allegations of retaliation.

Chmielewski said questions focused mostly on the issue of possible retaliation against employees who questioned Pruitt’s management or spending. Chmielewski said those employees include himself and five others who were either fired, moved to different jobs or took temporary leave.

He said the OSC also questioned him about Pruitt’s alleged “misconduct and misspending.”

Chmielewski said he was forced out of his EPA role after questioning Pruitt’s spending habits and other issues related to travel and management.

“EPA does not comment on matters involving OSC,” an EPA spokesman said in a statement.

The Office of Special Counsel probe was previously reported by The New York Times and Politico.