WASHINGTON (AP) -- An executive at Imperial Sugar Co. is expected to testify to Congress Tuesday about dangerous conditions at the company's Georgia refinery leading up to an explosion that killed 13 people in February.

A Senate subcommittee is reviewing the Port Wentworth, Ga., accident after a federal investigation found that Imperial had willfully and egregiously violated safety standards. The Occupational Safety and Health Administration has proposed nearly $9 million in fines, saying the blast was fueled by an excessive buildup of sugar dust.

Along with Graham H. Graham, an Imperial vice president for operations, several other safety experts were slated to testify, including the head of OSHA and the chairman of the U.S. Chemical Safety Board.