Mobil Oil Is Asked to Speed Inspection of Its Storage Tanks : Environment: Citing a need to reduce the risk of ground water pollution, the state asks for a new leak-detection and repair plan at Torrance plant.

Moving to reduce the risk of ground water pollution, water quality officials have asked Mobil Oil Corp. to speed the inspection and repair of its Torrance refinery’s 130 above-ground storage tanks.

In a March 18 letter to refinery manager Joel Maness, the state Regional Water Quality Control Board directed Mobil to devise a new leak-detection and repair plan and submit it to the board by April 15.

Mobil’s current program, approved by the board in 1988, calls for the inspection of 10 tanks a year. Water officials say they want the work accelerated because other refineries are carrying out similar programs far faster.

Robert Ghirelli, the water quality board’s executive officer, said: “Based on what others in the industry were doing, we felt Mobil ought to consider upgrading their program.”

The officials say the move would also bolster an ongoing effort by Mobil, supervised by the board, to clean up ground water pollution stemming from the north Torrance refinery and extending off site to the southeast.

“It only makes sense to stop leaks where they are occurring,” said Torrance City Councilman Dan Walker, who is vice chairman of the water quality board. “We’ve got to turn off the faucet.”

Mobil has not yet replied to the board’s letter. Maness said that before taking a position, the company must gauge how increased tank inspection would affect plant operations and how soon construction permits could be secured for the additional work.

Inspecting tanks commonly involves draining them, removing sludge and measuring the floor thicknesses with ultrasonic equipment. Making tanks leak-resistant often entails installing a double-layered bottom that channels leaking liquid to an exterior rim for easy detection.

“We’re trying to determine, ‘Can we change the program, can we be cooperative?’ ” Maness said. “If we can do it, I don’t see a particular problem.”

Mobil’s tanks are used to store petroleum products ranging from crude oil to high-test gasoline. Their capacities range from 30,000 barrels to 250,000 barrels, and their ages vary from 1 year to “very, very old,” Maness said.

Maness said he did not know the age of the oldest refinery tanks. However, he acknowledged that some date at least to the World War II-era and are held together by rivets instead of welds.

Maness also could not pinpoint when the refinery’s last tank inspection program took place, but said “it wouldn’t be any longer than 10 to 15 years (ago).”

As of the end of 1990, Mobil had inspected 33 of its tanks and had installed double bottoms on 14 of them, Maness said.

Water quality officials acknowledge that Mobil’s pace fully complies with the inspection program it agreed to carry out in 1988. But after witnessing inspection work undertaken by other refineries to stem ground water pollution, the officials say they have become convinced that Mobil’s program has room for improvement.

As examples, they cite Chevron and Shell.

Chevron last year completed a four-year, $100-million effort in which it inspected all 230 of the above-ground tanks at its El Segundo refinery, according to company spokesman Rod Spackman. More than 200 of the tanks were outfitted with double-layer bottoms, Spackman said.

Since 1987, Shell has been examining 35 tanks a year at its Carson refinery and 15 tanks a year at a chemical storage area on the refinery grounds, said Harry Hogue, an environmental engineer with the company. Hogue says the effort will involve installation of double-bottoms on a third of the oil refinery’s 300 tanks and most of the 80 to 90 tanks in the chemical storage area.

“Double-bottoming a tank is a little over a million bucks,” Hogue said. “. . . (But) it’s the surest way to see if you have a problem.”

Underlying the letter to Mobil is concern that leaky tanks could undermine efforts to control ground water pollution at the refinery.

The pollution has contaminated a portion of one of the South Bay’s shallow aquifers, but it is unclear whether contaminants have reached the deep aquifers from which the region draws some of its drinking water.

A Mobil monitoring well on the refinery grounds detected trace amounts of contaminants in one of the deep aquifers, called the Lynwood, according to test results filed with the water quality board in January. But board officials say the result was not confirmed in follow-up tests and may have been due to lab error.

“There’s a lot of uncertainty there because it was so close to the (minimum) detection limit,” said J. T. Liu, a water engineer with the board. “But we are asking that it be closely checked.”

Maness says ground water contamination at the plant is under control. The refinery carefully monitors tank levels and will overhaul any tank that appears to be losing its contents, he said.

If there are leaks, Maness said, ground water cleanup under way at the refinery will ensure that pollutants are removed. In that effort, contaminated ground water is being pumped above ground, stripped of pollutants, and pumped back underground.

“We feel we have the leaks under control and are no longer contributing to the plume,” Maness said. “. . . And anything that would leak from the refinery today would be mitigated by the (cleanup) program.”

But board officials argue that aggressive leak detection is essential in guarding against further ground water pollution. Said Ghirelli: “If we don’t cut off the sources as quickly as possible, there’s a possibility that more stuff could get into the ground.”

Maness says that among Mobil’s concerns in deciding how to respond to the board is whether stepped-up inspections will hurt its operations. As an example, he said, Mobil must maintain its ability to accumulate large amounts of petroleum products for bulk pipeline shipments from the refinery.

“We need a certain amount of storage in front of us all the time,” he said.

A related question is whether the water quality board can force Mobil to speed tank inspection and repair if the company decides it cannot comply with the board request.

Asked if that would be possible, given the board’s approval in 1988 of Mobil’s current program, Ghirelli said: “You’ve asked a question that I have in my own mind and can’t answer. I think we’ll have to explore that if we’re not happy with the proposal we get from them.”

Councilman Walker says the board should consider enforcement action if Mobil resists. “This letter was couched in very polite language,” he said. “You always say, ‘Please,’ the first time.”