[Update] Severe Blaze Erupts at Los Angeles Port

Thick smoke from a smoldering fire started by a welder's torch at the Port of Los Angeles was preventing the movement of containers at the facility on Tuesday, because the foul air was too harmful for dock workers, officials said.

The fire broke out on Monday evening at a wharf at the Port of Los Angeles, the nation's busiest seaport, and at one point it had engulfed the entire 800-foot (244-metre) length of the wharf, Los Angeles Fire Chief Ralph Terrazas told a news conference.

Within less than two hours, the fire was mostly extinguished although it continued to smolder because of factors such as the presence in the pier of creosote, a flammable, oily substance used as a wood preserving agent, officials said.

The stubborn fire, which was characterized on Tuesday by high heat but not open flames, was sending off large plumes of smoke that could be seen and smelled from miles away, and firefighters were prepared to spend hours more battling the fire, said Los Angeles Fire Department spokesman Brian Humphrey.

"These fires often take many hours or even days to fully extinguish," Humphrey said.

The smoke on Tuesday was preventing operations at the port's eight cargo container terminals, because the air quality was too dangerous for dock workers to continue loading and unloading containers, said port spokeswoman Rachel Campbell.

Three terminals that handle bulk shipments of liquids were still operating, because they involve less labor, and one terminal for car shipments was still in use, she said.

"This port is an engine for Southern California and this nation, and its operations are critically important," Los Angeles Mayor Eric Garcetti said.

At the adjacent Port of Long Beach, the second busiest U.S. seaport, operators at three of the facility's six container terminals sent dockworkers home because of concerns over smoke, said port spokesman Lee Peterson.

Meanwhile, Los Angeles school officials said they had evacuated students from an elementary school near the port because of the smoke.

The fire at the Port of Los Angeles was started by a welder's torch, said Humphrey, who did not have other details on what kind of work the welder was doing at the time.

The fire damaged the wharf and may have harmed the structural integrity of a warehouse on the site, he said.