Oil Firm’s Noise Threat to Whales Nears OK : Environment: Exxon plans to use underwater air gun blasts to search for oil off Santa Barbara coast. Foes seek safeguards for sea mammals.

The Clinton Administration is on the verge of approving a plan by Exxon Oil Co. to explore for oil off the coast of Santa Barbara County using underwater seismic air guns loud enough to harm whales’ hearing.

The seismic air guns, used to locate oil deposits beneath the ocean, can fire compressed air blasts every several seconds that routinely reach 240 decibels--one of the loudest sounds humans create short of massive explosions.

The National Marine Fisheries Service, the federal agency responsible for protecting marine mammals, estimates that as many as 81 whales belonging to nine different species could be “disturbed” by Exxon’s 45-day survey in waters as close as four miles off Gaviota.

Nevertheless, the agency is expected next week to authorize the 117-square-mile project, provided Exxon agrees to take certain steps to minimize injury to whales.

The proposal has alarmed environmentalists, who say it could cause serious harm to whales and possibly overlap with the winter migration of gray whales, affecting far more animals than the federal government estimates.

“That’s a tremendously loud noise,” said Sara Wan, vice chairwoman of the League for Coastal Protection. “Part of it will take place during the migration of gray whales.”

But Exxon spokesman Bruce Tackett said protections required by the government would keep whales from harm. “We believe this activity is safe,” he said by telephone from Houston.

Exxon’s proposal to conduct seismic testing in the ecologically sensitive Santa Barbara Channel comes as environmentalists are increasingly criticizing noise pollution of the ocean by oil operations, commercial shipping, weapons testing and scientific experiments.

Last year, a proposal by Scripps Institution of Oceanography to test global warming by repeatedly transmitting 195-decibel sounds through the Pacific Ocean came under harsh criticism and was ultimately scaled back.

Given that the decibel scale is logarithmic, Exxon’s proposed 240-decibel blasts--fired in quick pulses--would be 32,000 times louder than the broadcasts planned under the global warming experiment. The noise, however, would not be audible to humans unless they were in the water near the survey.

Government officials and backers of Exxon’s project said the seismic survey is a standard operation using longstanding methods. The same region was surveyed as recently as 1991, said Lisle Reed, director of the federal Minerals Management Service, which also has jurisdiction over the project.

“We’re not doing anything that hasn’t been done before,” Reed said from his office in Camarillo. “This is not any activity that is outside the norm of activities that have been going on for 30 years on this part of the coast.”

The survey has become an issue this time, in part, because of new federal procedures that require the National Marine Fisheries Service to grant written approval for the “harassment” of protected species. If approved, Exxon’s survey would be the first to take place off California under the new rules. Before it can proceed, Exxon also needs the approval of the Minerals Management Service.

The oil company proposes to survey the area by making 55 passes on an east-west course over 45 days. The operation would continue 24 hours a day, but the air guns usually would be shut off when the boat is turning and lining up for its next run.

Exxon wants to undertake the study so it can locate remaining oil deposits in the offshore lease--four to 12 miles off the Santa Barbara coast--where it has three drilling platforms. The company has authorization to erect one more platform in the area, but may be able to extract the oil more efficiently using long-range directional drilling from its existing platforms.

Backers of the survey argue that it has environmental benefits because it would reduce the number of wells drilled in the area and thereby reduce the accompanying disturbance of the ocean bottom that drilling can cause.

“The seismic data collected from this type of survey is designed to allow Exxon to drill the least number of wells,” Tackett said. “In that sense, clearly there is both an environmental and a business benefit to it.”

But the California Coastal Commission has joined environmentalists in questioning whether safeguards to be imposed on Exxon by the federal government would be adequate to protect marine life. A telephone conference call among representatives of various agencies is scheduled today to try to work out a compromise.

Whale lovers, in particular, express concern that the survey could cause substantial auditory damage to the marine mammals, which are highly dependent on their sense of hearing.

Among the species that could be affected, according to the fisheries service, are blue, fin, humpback, sperm, Pygmy sperm, sei, minke, gray and Bryde’s whales.

Of these, all but the gray whale are listed as endangered, and the gray, which was taken off the endangered species list because of its dramatic recovery in recent years, still is afforded considerable protection under laws that protect marine mammals.

Fisheries officials say that smaller marine mammals, such as dolphins and seals, would not be affected by the air gun blasts because the sound is in a lower frequency than the range in which they communicate.

Ken Hollingshead, a biologist with the fisheries agency, estimated that as many as 81 whales belonging to the nine species would come in range of the air guns during the survey.

“The animals would have a number of instances where they would potentially be affected by the noise,” he said.

Because the sound is dampened quickly as it travels through water, he estimated that the blasts would cause auditory damage to the whales only if they were within 500 feet of the sound source.

To try to prevent such harm, the fisheries agency plans to require Exxon to have observers on board to halt the survey if a whale is observed within 300 feet. In addition, when starting up, the survey crew would be required to turn up the sound level gradually over a five-minute period so that animals in the area could move away.

Environmentalists and California Coastal Commission members question why observers would not stop the survey when the whales come within 500 feet of the sound.

The also are concerned that the survey will not be completed before gray whales begin migrating through the area, which is expected about Dec. 15.

Exxon plans to begin the survey Nov. 1 and continue for at least 45 days. If the presence of whales or bad weather causes delays, the survey could extend into the migration time of the gray whales.

Reed, the Minerals Management Service regional director, said the survey would stop if it was not completed by the time of the migration.

“They would have to get their work completed before the whales showed up,” he said. “If they don’t get out of the water by Dec. 15, we just have to call a halt to the thing and put it off for a year.”

But environmentalists point out that the proposed operating permit has no deadline for completion of the survey and question how Exxon could be required to halt.

“We want it to be specified that’s what they have to do,” said Susan Jordan, an activist who helped lead the fight against Scripps’ ocean sound experiment. “We want it down in writing.”