The U.S. Chemical Safety Board is operating without a permanent leader. Its chairman has been forced to resign, following accusations of mismanagement.

A White House official says Rafael Moure-Eraso stepped down Thursday at the administration's request. The official spoke on condition of anonymity to discuss personnel matters.  

The National Safety Council says the independent federal agency under Moure-Eraso repeatedly fell under scrutiny for board departures, delayed investigations and other issues. Members of the Senate Environment and Public Works Committee had accused Moure-Eraso of violating his oath of office and the law. Committee members had requested his resignation.  

The board is responsible for investigating chemical accidents. Its members are appointed by the president and confirmed by the Senate.  

President Barack Obama has nominated Vanessa Sutherland to succeed Moure-Eraso.