After crude oil gushed from a ruptured pipeline into Bull Creek in Granada Hills in April, 1986, Mobil Oil Corp. sought to assure pipeline regulators that it had things well in hand.
In a letter to the State Fire Marshal's office, Mobil described the leak as an isolated incident caused by corrosion and blamed it on an ineffective pipe coating the company no longer used.
But in the next few years, more corrosion leaks occurred in pipe protected by coatings that were supposed to be better. The most recent was on Jan. 31, when 74,000 gallons of tarry crude flowed from broken pipe in Valencia, some of it befouling the Santa Clara River.
By then, Mobil, the country's second-biggest oil company, had given up on the existing pipeline. It had poured millions of dollars into oil-spill cleanup, and cleanup expenses seemed certain to remain high as long the badly corroded line remained in service. So at the time of the Valencia spill, Mobil was well along in planning a new $88-million, 92-mile pipeline to bring crude oil from Kern County to its Torrance refinery.
The pipeline will traverse the San Fernando Valley and the Westside, following Sepulveda Boulevard for much of the way. And the new line, according to Mobil, will feature a state-of-the-art coating system, as well as other safety improvements.
But with Mobil poised to start construction, it remains to be seen if the new pipeline will avoid the problems that have made the existing line a dismal performer. At times in the past, Mobil was overly optimistic about the coatings it used to stem corrosion. And human error seems to have been a factor in some accidents.
Since late 1985, the pipeline has suffered numerous leaks and ruptures--some of them small and some occurring during hydrostatic testing, when water is flushed through the pipe at abnormally high pressure to check for weak spots.
Counting only the seven leaks that exceeded a federal reporting threshold of 50 barrels--or 2,100 gallons--the risk of accidents during the five-year period was about 10 times higher than for the average crude oil line of similar age, according to data contained in the environmental impact report prepared for the new pipeline.
"The line's a chronic leaker," said Jim Wait, chief of the Fire Marshal's pipeline safety division, which regulates intrastate pipelines such as Mobil's.
Many petroleum pipelines crisscross Los Angeles, but Mobil's is unique for its "inordinate" number of spills, said Ken Cude, division engineer for the city Department of Transportation.
Mobil spokesman Jim Carbonetti acknowledged the pipeline's problems, adding: "That's why we want to replace it."
Although the frequency of spills is an embarrassment to Mobil, it has made the new line easier to sell. For example, the Fire Marshal and city transportation department have been unabashed supporters, citing the repeated failures of the existing line.
Although opponents of the project, banded together as the Coalition Against the Pipeline, have filed suit to block construction, the continuing threat of spills from the existing line has almost surely cost them allies.
Portions of the pipeline are 50 years old--a fact officials of Mobil and the Fire Marshal's office are quick to mention. But other experts say age alone is no excuse--that a pipeline properly installed and maintained virtually lasts forever.
"There's something else that's going on, no question about it, because age itself is not a problem with the pipelines," said Richard Beam, deputy associate administrator of the federal Office of Pipeline Safety, a branch of the U.S. Department of Transportation.
"It's a question of how the line was designed, constructed and what its maintenance record is," Beam said.
In fact, three-fourths of the pipeline is 20 years old or less, and it is on these sections that most of the recent accidents have occurred.
Last January's spill in Valencia, another spill in Valencia of 1,040 gallons in May, 1990, a 132,000 gallon spill in Encino in September, 1988, and a 105,000 gallon spill in Lebec in June, 1987, occurred in pipe sections installed in 1971, 1972, 1975, and 1971, respectively.
External corrosion was blamed for each of these accidents. In each case, the protective pipe coating lining the outer wall of the pipe "disbonded"--or tore away--allowing moisture to corrode the steel.
There are a number of reasons why a coating may disbond. It may be improperly applied in the factory, or damaged during installation. Or it may simply be the wrong coating for the job at hand. It must be able to withstand "soil stress"--the beating it takes as the pipeline moves in the ground in response to changing temperature or pressure. And on certain pipelines, like Mobil's, it must be capable of surviving high temperatures. Mobil's is a "hot" oil line, in which the tarry crude is heated up to 180 degrees to keep it flowing.