Helicopter Crashes; 5 Missing : Accident: Aircraft clipped power lines and sank in strait near San Pablo Bay, near San Francisco, during survey of oil spill residue.

A private helicopter with five people on board crashed and sank Saturday in a strait near San Pablo Bay, northeast of San Francisco, apparently after clipping power lines near the town of Crockett while on a low-altitude survey of residue from a 3-day-old oil spill.

Coast Guard officials said the helicopter plunged into waters about 80 feet deep. There was no evidence of survivors as two dozen divers from the U.S. Navy and two Bay Area police agencies searched the channel well into the evening.

The Coast Guard identified one of its officials, Lt. Carl Johnson, 31, of Concord as among the missing.

Also missing were the helicopter pilot, Pat Walters of Novato; two environmental specialists from the state Department of Fish and Game, Greg Cook, 44, of Napa and Sonia Hamilton, 35, of Vallejo, and a representative of an emergency-cleanup company, Clean Bay, whose identity was not released.

Two fishermen told the Associated Press that they saw the low-flying helicopter and waved to the pilot just before it snagged the power lines.

“As soon as (the pilot) waved, he hit this cable and he pulled his arm back in and that was it. The thing just dropped. It was intact. The rotors were bent up, but there was no explosion,” said Ron Moniz, 41, of Benicia.

Moniz and his fishing companion, Richard Shoup of Benicia, hurried to where the helicopter entered the water, about 50 yards from where they were fishing, but the craft had sunk.

“The aircraft just dropped and sank within five seconds,” Moniz said.

The fishermen circled the area as other witnesses radioed authorities, but they recovered only a small piece of fiberglass.

Clean Bay Manager Stephen Ricks said that the five had gone up in the helicopter early Saturday afternoon to investigate reports of a residual oil sheen in Carquinez Strait. That narrow body of water separates San Pablo Bay from Suisun Bay, 20 miles from San Francisco. “My understanding is that (the helicopter) hit some power lines as it was passing over the Carquinez Bridge and went down,” Ricks said. That towering, twin-span steel cantilever bridge carries Interstate 80 between San Francisco and Sacramento.

Coast Guard spokesman Stephen Edge said the helicopter crashed about 1:30 p.m. near a huge waterfront sugar processing plant owned by C & H Sugar Co. The aircraft had taken off about half an hour earlier from Buchanan Field in Concord.

Patrick Corr, who helped organize the flight, said the Bell 207 Jet Ranger was owned by Air There and based at Gnoss Field in Marin County. Corr said his company, Helicopter Adventures in Concord, could not accommodate Clean Bay’s schedule and arranged for Walters to make the flight.

Clean Bay had skimmed several barrels of oil off San Pablo Bay on Wednesday after the tanker Overseas Boston had dumped oil-contaminated waste water over the side that day, Ricks said.

Damage to wildlife was minimal after the spill, he said, and no oil washed up on shore. Ricks said his outfit was continuing to monitor the situation, investigating reports of residual oil seen floating on the bay.

Ricks said Clean Bay is a private, nonprofit cooperative formed by oil companies to react to oil spills from tankers or from the refineries along San Pablo and Suisun bays on the northern Contra Costa County shoreline.

San Francisco Bay refineries are a major destination for oil from Alaska, but Ricks said he did not know if the Overseas Boston was inbound or outbound at the time of the spill. He said the tanker was not unloading oil when the spill occurred.

Times staff writer Greg Krikorian contributed to this story.