A Singapore company agreed to plead guilty to environmental violations and pay a $10 million fine for an oil spill caused by the 2004 wreck of one of its cargo ships off Alaska, the U.S. Justice Department said on Tuesday.

IMC Shipping Co. Pte. Ltd. filed a plea agreement in U.S. District Court in Anchorage to settle charges stemming from the wreck of the Selendang Ayu, which resulted in the spill of 335,732 gallons (1.5 million litres) of fuel oil and the death of six crew members.

The ship, owned by a subsidiary of privately held IMC Group, drifted for two days in a Bering Sea storm before grounding off an Aleutian island, splitting in half and spilling fuel and 60,000 metric tons of soybeans.

The spill, the worst in Alaska since the 1989 Exxon Valdez disaster, was exacerbated by harsh winter weather, low-light conditions and the remote but biologically important location of the grounding. More than 1,600 dead seabirds were found in the spill's wake, according to federal officials.

The 738-foot (225-meter) ship grounded off the uninhabited west side of Unalaska Island, adjacent to the sprawling Alaska Maritime National Wildlife Refuge. Cleaning up the spill lasted until the summer of 2006.

"It was an extremely difficult cleanup," said Gary Folley, who oversaw the effort for the Alaska Department of Environmental Conservation.

The plea deal is pending court approval.

Six crew members died during the wrecked ships's evacuation. A wave struck the U.S. Coast Guard helicopter that was hoisting crewmen from the vessel and the helicopter crashed. The Coast Guard rescued the other 20 crewmen.

IMC Shipping still faces civil fines to be assessed by the state and federal governments for natural resource damages. The state is calculating the civil fine it will levy, Folley said.