BP Plc (NYSE:BP) has agreed to pay a record $50.6 million fine for safety violations from a deadly 2005 explosion at its troubled Texas City, Texas refinery, U.S. Labor Secretary Hilda Solis said Thursday.

BP also agreed to allocate $500 million to fix safety problems at the refinery and accepted a set program of safety inspections and review by the U.S. Occupational Safety and Health Administration.

"The size of the fine rightly reflects BP's lack of regard for worker safety," Solis said in a Thursday afternoon conference call.

OSHA will continue to seek $30 million in fines for new safety violations found by government inspectors at the refinery.

BP's global head of refining said the company would work with OSHA to improve refinery safety.

"BP has a stated goal to become a leader in process safety and we look forward to working collaboratively with OSHA to achieve an injury-free workplace in our operations," said Ian Conn, global head of refining.

In October, the U.S. Occupational Safety and Health Administration slapped BP with a record $87.4 million in proposed fines for safety violations at the Texas City refinery, which was the site of a deadly explosion in 2005.

In the October announcement, Solis said old and new safety violations found by OSHA at BP Texas City, the nation's third largest refinery, "could lead to another catastrophe" like the 2005 explosion that killed 15 workers and injured 180 others.

BP defended its efforts to improve safety at the 465,000 barrel per day (bpd) refinery, located about 50 miles south of downtown Houston.

The company also filed an appeal of the fine.

Last week, Texas Attorney General Greg Abbott sued BP for a 40-day release of excess pollution including carcinogenic benzene in April and May at the refinery.

The company was also hit with a $10 billion federal class action lawsuit earlier this month for the April-May pollution, which BP reported to state regulators.

Houston attorney Tony Buzbee, who filed the class-action suit, which had over 12,000 plaintiffs, welcomed the Labor Department's action.

"We believe the fine to be appropriate and welcome the government's efforts in our quest to force this British company to comply with U.S. and Texas Law," Buzbee said. "BP's record rivals the worst in U.S. history."

Last year, BP pleaded guilty to federal criminal charges in the 2005 explosion and paid a $50 million fine. (Editing by John Picinich)