The offshore mooring procedure used at Huntington Beach and at a dozen other terminals on the California coast is an especially precarious way of transferring oil between tankers and refineries, the State Lands Commission director says.
"That's the most risky procedure for loading or unloading petroleum products," said Charles Warren, executive officer of the commission, which controls the tidelands where some terminals are located.
But until the Huntington Beach spill last week, the safety record at such spread moorings was good.
It was a spread mooring that the crew of the American Trader was trying to hook up to Wednesday when the oil spill occurred. In the process of unloading the oil, the tanker apparently hit its own anchor on the bottom, punching at least two holes in the hull and spilling nearly 400,000 gallons of crude oil into the sea.
Spread moorings are offshore terminals used by tankers to load and unload oil at sea. Rather than pull into ports, the tankers are held in position by buoys and are hooked up to undersea pipelines which lead to refineries on shore.
Since the devastating Exxon Valdez spill in Alaska last year, Warren said, the State Lands Commission has asked for authority to inspect all marine oil-transfer terminals. The Legislature is considering the request, he added.
Critics say the Huntington Beach spill is evidence that transporting oil offshore by tanker poses a threat to the environment.
But Coast Guard data collected over the last three years indicates that until last week's accident, there has been little spillage in mishaps at underwater terminals--less than 100 gallons of oil in all.
Lt. William Whitson, chief of port safety and security in Long Beach, acknowledges that it is difficult--if not impossible--to verify the size of many of the spills reported by oil companies or shippers. Failure to report a spill, Whitson noted, carries a $10,000 fine.
Still, environmentalists suspect that some spills go unreported.
The Coast Guard is responsible for making yearly inspections of the spread mooring terminals, which are found off El Segundo, Huntington Beach, Carlsbad, Santa Barbara County, San Luis Obispo County and in Monterey Bay.
Most of the spread moorings predate World War II, when oil fields were opened in the Santa Barbara Channel, according to Jerry Aspland, president of Arco Marine and a former tanker captain.
Spread moorings at Carpinteria, Ventura and elsewhere have closed down as oil fields became depleted and other alternatives were found. Most crude oil for Southern California refineries arrives by underground pipelines or is unloaded from tankers at berths inside the ports of Los Angeles and Long Beach.
Berths within ports are considered safer than spread moorings. But even the berths have not proved fail-safe.
In 1985, a spill that occurred at a Mobil facility inside the Port of Los Angeles resulted in $62,000 in civil fines, said Richard Harris of the state Regional Water Quality Control Board.
In general, the offshore terminals handle tankers much smaller than the behemoths sailing from Valdez to the ports of Los Angeles and Long Beach.
At the Chevron refinery in El Segundo, for instance, about 12 of the smaller tankers moor each month to unload crude oil offshore.
The Chevron transfer procedure is similar to that used at the Golden West terminal off Huntington Beach. The tanker is steered into position and fixed to a series of buoys that anchor it in place. Unlike some terminals, where ships maneuver under their own power, tankers at the Chevron mooring use tugs to move into position.
Once anchored, the tanker connects to an underwater pipeline that goes ashore. All the oil pipeline connections are made on deck, and usually no oil spills into the sea, Spackman said.
"If we spilled one cup of oil off one of our moorings, it would be reported to the Coast Guard," he said.
Only about 60% of Chevron's crude oil comes by way of the ships. The rest is brought to El Segundo in underground pipelines, a method that Chevron agrees is more desirable.