EARTHQUAKE: THE LONG ROAD BACK : Alarcon Seeks to Block New Oil Pipeline Agreements : Spills: The councilman wants a moratorium until the investigation of a quake-related rupture in Pacoima is completed.

Angered by a blaze fueled by oil from a quake-ruptured pipeline in Pacoima, Los Angeles City Councilman Richard Alarcon said Wednesday that he will seek a moratorium on new agreements to operate such underground pipelines in the city.

The moratorium is likely to delay the renewal of expired franchise agreements between the city and four petroleum companies that want to continue pumping oil through existing pipelines under city streets.

Alarcon’s move may also affect the city’s consideration of a pipeline proposed to run parallel to railroad tracks in the northeast San Fernando Valley, just a few blocks east of the site of the Jan. 17 fire, which injured one man and burned 17 cars and three homes.

That pipeline, which would carry oil 52 miles from Santa Clarita to Wilmington, is scheduled to be discussed today at a meeting of the Los Angeles Board of Transportation Commissioners.

Alarcon, whose district includes the Pacoima neighborhood burned in the fire, said he will ask the City Council to adopt the moratorium until an investigation of the rupture on Wolfskill Street can be completed.

The rupture occurred at a weak acetylene weld in the line, according to an official from the State Fire Marshal’s Office, which oversees pipeline safety. The crude oil that spewed into the street ignited, sending walls of flames racing down three city blocks.

It was one of eight breaks that occurred along a 35-mile stretch of the Four Corners Pipeline. One rupture killed hundreds of fish and other wildlife in the Santa Clara River in Valencia.

Alarcon had hoped to find a way to break the city’s agreement with owners of the line, but was told Wednesday that the city has found no evidence that Atlantic Richfield Co. violated the terms of a franchise agreement allowing the pipeline to carry oil under city streets.

Alan Willis, a senior engineer who oversees city franchises, said the city may not have the power to break the 21-year agreement, which expires in 2000, and thus close the pipeline.

“I’d like you to sell that to the kid in the Sherman Oaks Burn Center,” Alarcon responded, referring to a 21-year-old man burned in the fire.

Robert G. Gorham, a pipeline safety engineer at the State Fire Marshal’s Office, called the fire “very unusual” because the crude oil that spilled is difficult to ignite.

“We rarely have crude oil fires,” he said.

In addition, the oil in the ruptured pipeline was not under pressure and the line was used only as a backup for a newer line that runs parallel to it, Gorham said.

He added that his agency has not yet determined how the oil was ignited.

In hopes of replacing weak segments in the city’s 500-mile pipeline network, the State Fire Marshal’s Office has asked all firms that operate pipelines in the city to identify where old acetylene welds have been used to join pipe segments.

Gorham said his agency hopes to persuade the firms to replace the sections with acetylene welds with stronger segments using modern arc-welding techniques.