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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.


SAN FRANCISCO — 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.

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