Gas Leak Shuts Down L.A. Harbor : Shipping: Highly flammable chemical is leaking aboard freighter. Threat of fire or explosion could force wide evacuation.

The Port of Los Angeles was closed to major cargo and passenger ships on Friday after highly flammable trifluoropropene gas leaking from a one-ton canister on a freighter forced the Coast Guard to shut down the main channel.

Officials said the threat of fire or explosion meant that substantial portions of Terminal Island and San Pedro might have to be evacuated if the leakage at Berth 233, where the freighter Ever Group is docked, proves more dangerous than initially estimated.

They said a large-scale evacuation also might be necessary if the Coast Guard decides to tow the ship past San Pedro and out of the harbor to unload its contents at sea.

Sampling probes were being lowered into the freighter’s hold Friday night to determine the concentrations and precise makeup of the gases in the cargo bay. The officials said that until these tests are completed and the leak is neutralized, a general evacuation remained a possibility.

On Thursday night, 27 “non-essential personnel”--most of them relatives of staffers--were evacuated from the federal penitentiary at Terminal Island about half a mile south of the ship. They were housed in a Long Beach hotel. Officials said arrangements had been made to house the 1,127 inmates at other prisons and jails if further evacuation proved necessary.

Half of the approximately 100-member Coast Guard contingent at Reservation Point--the southernmost point on Terminal Island--were evacuated before dawn on Friday.

Several commercial fishing vessels and sportfishing boats berthed along the main channel were ordered to remain at their docks on Friday, but business was pretty much as usual at the Ports ‘O Call shopping and restaurant complex, across the main channel and about a mile below the berth where the gas was leaking.

It was the first time the harbor had been shut down since the explosion of a tanker in 1976 that claimed nine lives. There was no prediction when the port would reopen.

Los Angeles city fire officials said the canister that was leaking the nontoxic trifluoropropene was one of 15 located in a large cargo container stowed deep in the hold of the Taiwan-registered 882-foot freighter.

The officials said that because the colorless gas is about three times heavier than air, it was slow to disperse in Friday’s relatively light winds.

“And there are other extremely hazardous (explosive) chemicals on that boat,” said Patrick O’Donnell, an official with the Los Angeles County Health Department. “We’re talking about large quantities. That’s what the trouble is.”

The leaking gas is not lethal to breathe. However, it acts like an anesthetic and its odor can make people nauseous.

According to port spokeswoman Julia Nagano, at least two port police officers and two longshoremen who were on the scene when the vapors were first detected became ill after breathing them. They were treated at a hospital.

Spokesmen for the Port of Los Angeles said the tie-up was costing hundreds of thousands of dollars in delays at the second-busiest harbor in the nation.

The Azure Seas and the Southward--passenger ships arriving from cruises off the Mexican Riviera--were diverted to berths in Long Beach Harbor on Friday, and four cargo ships were stalled at anchor in the outer harbor. Other freighters, scheduled to sail on Friday, were marooned at their docks. Officials said such delays typically cost about $40,000 a day per ship.

The Los Angeles Fire Department said it first began receiving reports of a strange smell in the main channel area on Wednesday, but because of shifting winds, the source of the leak was not pinpointed until Thursday night.

The decision to seal off the main channel between Reservation Point and the Vincent Thomas Bridge--a distance of about 2 miles--was made at about 10 p.m. Thursday to create a safety zone around the Ever Group. Coast Guard cutters were posted at each end of the channel to block traffic.

The main channel is the only route that big passenger and cargo ships can use to reach the berths at the Port of Los Angeles.

There is a smaller, secondary route--the Cerritos Channel--that some smaller vessels can use to enter the Port of Los Angeles through the adjacent Long Beach Harbor. However, for much of Friday, the Commodore Schuyler F. Heim Drawbridge on the Terminal Island Freeway was stuck in the closed position, sealing off the Cerritos Channel.

Deputy Fire Chief Donald F. Anthony said the trifluoropropene gas--used in the manufacture of plastics--had arrived here by rail from the Midwest and was loaded onto the Ever Group for shipment to the Far East.

The Fire Department said the gas was believed to have been manufactured by Great Lakes Chemical Corp., based in West Lafayette, Ind.

Greg Griffith, a spokesman for the firm, said in a telephone interview that the company had yet to confirm that it had shipped the gas that was leaking from the canister aboard the Ever Group. However, he did say that the vessel was carrying other shipments from the company. Griffith declined to name the destination of those shipments.

Los Angeles Harbor has been the site of several devastating ship explosions in the past.

On Dec. 17, 1976, a spark ignited fumes aboard the oil tanker Sansinena at the Union Oil Co. Terminal in San Pedro, setting off an explosion that rocked buildings for miles, killing nine men and causing damage estimated at $21.6 million.

In June, 1947, the tanker Markay was taking on aviation fuel at Mormon Island when a blast tore through the ship, killing 12 people and causing $10 million in damage. Three years earlier, an explosion on two Navy ships docked at Berth 223 killed 16.

The worst harbor explosion in history took place on Dec. 6, 1917, when a munitions ship blew up in Halifax, Nova Scotia, killing 1,654 people and leaving much of the city in ruins.

Times staff writers David Ferrell, Sheryl Stolberg and Jocelyn Stewart contributed to this story.