Federal Emergency Management Agency Administrator David Richardson resigned on Monday and will return to the private sector, the agency confirmed.

“The Federal Emergency Management Agency (FEMA) and the Department of Homeland Security (DHS) extend their sincere appreciation to the Senior Official Performing the Duties of the Administrator, David Richardson, for his dedicated service and wish him continued success in his return to the private sector,” a FEMA spokesperson told The Hill news outlet in a statement.

The spokesperson added that FEMA Chief of Staff Karen Evans will take over the role of administrator starting on Dec. 1.

The agency did not explain the reason for Richardson leaving.