A vast part of the U.S. oil industry was paralyzed on Friday hours before powerful Hurricane Rita's (search) expected landfall on the Texas coast.

The storm, packing 135 mile-an-hour winds, already forced shut 15 big U.S. refineries, adding to the four that had remained shut after Hurricane Katrina swept through the area earlier in the month.

In total, nearly 30 percent of U.S. refining operations are closed, according to the U.S. government on Friday, raising worries about fuel shortages and spiking pump prices.

The NHC expects Rita to continue moving toward the northwest at 10 mph for the next 24 hours, which would put the core of Rita over the southwestern Louisiana and upper Texas coasts early Saturday.

The production of crude oil and natural gas offshore has also been slashed after companies removed workers from rigs that are expected to get battered again by massive waves and violent winds.

The nation's biggest offshore oil port, the Louisiana Offshore Oil Port (search) (LOOP) in Louisiana, was also forced to shut down its operations, which will curtail imports and offloading of domestic crude produced in the Gulf.

The New York Mercantile Exchange (search) on Friday declared force majeure (search) on September natural gas deliveries due to the closure of the Sabine Pipeline (search) which operates the key Henry Hub delivery point in Erath, La.