SPILL AT A GLANCE

THE SPILL

Ship: American Trader.

Oil spilled: Estimated 300,000 gallons, Southern California’s biggest in two decades.

When: About 4:30 p.m. Wednesday

Where: Washing ashore along a 12-mile stretch as far north as Sunset Beach. Several fingers of the slick were within two miles of Long Beach. Laguna Beach was also concerned that slick might spread south to beaches; cleanup company was on call there.

Ocean depth: As little as 50 feet in some spots in the sea berth, 60 feet or more in area where ship maneuvers.

How: Coast Guard suspects the ship ran over its port anchor while maneuvering into a U-shaped nest of seven mooring buoys off Huntington Beach. As crew pulled up anchor, it apparently wrapped around bow and put two holes and a dent in the starboard bottom of hull. Ship also may have hit sea bottom, causing anchor to puncture hull.

The Slick: Eighteen square miles. Less than two-thirds of the oil remains in water. More than 7% of the oil was recovered by skimmer boats.

Oil left: Damaged tank still contains more than 1 million gallons of oil, but it apparently is not leaking. Tank’s oil level sank just far enough to match level of water outside ship’s hull. Second tank that is possibly damaged contains 2 million gallons. Both tanks were being drained Friday.

THE SHIP

Built: In 1969 by Sun Shipbuilders and Drydock Inc. of Philadelphia, now defunct. Named America Sun. Acquired by American Trading Transport Co. Inc. on July 11, 1989, and renamed American Trader. Chartered by British Petroleum Co. of North America, which was operating it at time of spill.

Width: 125 feet.

Length: 800 feet.

Hull depth: 42 or more feet below water surface at time of incident.

Anchor: More than 10 feet long.

Oil capacity: 23 million gallons. More than a dozen tanks, some of them for ballast and ship waste. Fully loaded at time of incident.

Itinerary: Planned to unload more than 12 million gallons at the sea berth, where a pipeline connects to a Santa Fe Springs Refinery. The rest was to be delivered to the Port of Long Beach.

THE CLEANUP

Offshore: At least 9 skimmer boats are on scene. Coast Guard was also there to monitor operation.

Beaches: As oil comes ashore, cleanup crew in slickers use absorbent pads on sand. By Friday, 800 bags of pads were collected by about 400 hired workers on hand. Bulldozers also on scene to dig up oil-soaked sand. Thousands of residents volunteered to help, but many were turned away by firm because of liability concerns.

Preventive measures: Rubberized booms were set up to keep oil from estuaries at Bolsa Chica State Reserve, Anaheim Bay, Upper Newport Bay and Santa Ana River.

Options: Officials have ruled out chemical dispersants, which break up the slick. Dispersants can reduce the chance that oil will wash ashore but cannot be used in shallow areas because of possible toxic effects on bottom-dwelling organisms, fish or shellfish.

Birds: 49 oil-covered shore birds washed up after spill, 12 of them dead. If slick reaches Bolsa Chica wetlands at north end of Huntington Beach, it could be devastating to one of California’s largest ecological reserves. California brown pelican, California least tern, the light-footed clapper rail and the salt marsh bird’s beak, an upper marsh coastal plant, are endangered species in the wetlands.

Other wildlife: Could take a deadly toll on fish and perhaps marine mammals such as sea lions. Oil mats mammals’ fur, making them susceptible to cold and less buoyant. About 30 seals were spotted Friday on mooring buoys near the tanker but apparently were unharmed. More critically endangered may be tiny links in aquatic food chain--anchovies, mussels and barnacles.

Source: U.S. Coast Guard, Times staff