A ship carrying about 300,000 gallons of crude oil and other liquids from North Dakota has capsized off the coast of Florida, killing at least four people and spilling hundreds of thousands of gallons of fuel into the Gulf of Mexico, officials said Friday.

A tanker transporting about 300 barrels of crude, or nearly 12,000 barrels of oil, capsized Friday off the Florida coast about 4:30 p.m.

EST, according to the Florida Emergency Management Agency.

The ship is owned by Cargill, which is headquartered in Texas.

Cargill has not said what caused the accident.

A Cargills spokesperson declined to comment Friday.

The company said the vessel was in port and scheduled to depart in the morning for New Orleans.

The cause of the accident is under investigation, the Florida Department of Emergency Management said in a statement.

The Coast Guard is assisting with the search.

The vessel was being used to transport cargo in a “very hazardous” region and was carrying about 200 barrels of fuel.

Cargo ships are popular with foreign shipping companies looking to bring in oil.

U.s. shipping capacity for crude oil was about 1.5 million barrels per day in March, according the Federal Energy Regulatory Commission.

The accident has the potential to cost the U. S. economy more than $400 million, according a separate report by the National Association of Coast Guard Ships.