CHARLOTTE, N.C. — North Carolina’s environment office chief under former Gov. Pat McCrory has retired weeks after the department — now with another administration’s leadership — suspended him from a lesser job within the Cabinet agency.

The Department of Environmental Quality confirmed Wednesday that Donald van der Vaart submitted his retirement letter Tuesday. The career state employee was named DEQ secretary by the Republican McCrory in early 2015.

A day before Democratic Gov. Roy Cooper was sworn in last Jan. 1, van der Vaart demoted himself to his previous job as a section chief in the Division of Air Quality instead of getting fired, shielding himself from a fate many McCrory political appointees in key positions expected.

DEQ confirmed earlier this month he was placed on paid investigatory leave. A Nov. 1 memo suspending van der Vaart obtained by WBTV, which first reported his retirement, said the department would investigate “concerns about your conduct and recent actions that may have compromised” the air quality division and DEQ.

Department spokeswoman Bridget Munger declined to comment further Wednesday about the retirement, citing confidentiality in personnel issues. But van der Vaart told WBTV in an interview that agency officials were unhappy with an article he co-wrote and his appointment to a science advisory board by Environmental Protection Agency Administrator Scott Pruitt.

“I’m afraid it’s probably a little more about politics, but it’s still sad nonetheless,” van der Vaart told the Charlotte station about his suspension.

Critics of President Donald’s Trump administration and of Pruitt are worried about the EPA’s future and any rolling back or delaying of environmental policies pushed by then-President Barack Obama.

As DEQ secretary, van der Vaart criticized Cooper while he was attorney general for failing to oppose Obama’s greenhouse gas emissions reduction plan. Van der Vaart had joined two dozen other states in suing to block the Obama administration’s Clean Power Plan, calling that federal overreach. But Michael Regan, Cooper’s environment secretary, withdrew the department from the lawsuit, saying it wasn’t a good use of taxpayer dollars.

In his retirement letter to Regan, van der Vaart wrote that he had written 30 articles over the years following similar procedures as now.

“This administration is moving to stifle my contributions to scientific and legal discourse in professional journals,” he wrote. “This is deeply troubling.” He also wrote there was no reason to believe that his participation on the advisory board would be anything but positive for the state and for DEQ.

Van der Vaart wrote he had always expected to return to his previous air quality division position when he was no longer secretary.

John Evans, who was van der Vaart’s top deputy while he was secretary, also remained in the department under Cooper. He co-wrote the September article with van der Vaart calling for repeal of a Clean Air Act provision. The department also placed Evans on investigatory leave earlier this month.