Electrical Cause Is Ruled Out in Seal Beach Pier Blaze : Inquiry: Investigators switch focus to possible ‘incendiary source.’ There is no evidence it was intentionally set, city manager says.

A malfunctioning electrical system has been ruled out as the cause of Saturday’s fire at the Seal Beach Pier, and officials are now investigating whether an “incendiary source” brought onto the boardwalk sparked the blaze.

City Manager Jerry L. Bankston said Thursday that fire investigators have not identified the source of the fire and are still looking for clues. He stressed there is no evidence that the fire was intentionally set.

Investigators and fire engineers believe that the heat source somehow ignited a plastic gas line that runs beneath the old wooden pier from its base to the Ruby’s restaurant at the end of the structure, Bankston said.

The surprising turn in the fire investigation contrasts with preliminary reports from officials that pointed to the pier’s electrical system as playing a role in the blaze that temporarily stranded people on the pier.

But an extensive examination of the system by both fire investigators and three electrical engineers found that it did not cause the blaze. Officials said that the high-voltage conduit that runs the length of the pier was burned on the outside but not on the inside, Bankston said.

Another indication that the electrical system did not malfunction came from computer records from Ruby’s restaurant, which showed that the establishment’s cash registers, clocks and kitchen equipment continued to receive power at least 10 minutes after the fire was reported, Bankston said.

“We had an opportunity to put together time sequences,” he said. Ruby’s “still had electricity 10 to 13 minutes after the first calls were made to Fire Department dispatch.”

To get a better look at the area of the fire, portions of the pier’s wood deck were pulled up, labeled and reconstructed. Investigators found no junction boxes and detected no evidence of spliced electrical lines in the area of the fire, Bankston said.

The Saturday blaze temporarily stranded more than 100 people at the end of the boardwalk but injured no one. Witnesses reported hearing several small explosions just before the fire, possibly arcs of electricity. Bankston said the arcs could have occurred when the fire burned electrical lines.

Rumors have also circulated in the city about someone operating a barbecue at the pier around the time of the blaze. Officials said they don’t know whether that report is true but added they would welcome any solid information that the public can provide.

Bankston said investigators are still working to identify the fire source and determine if--and how--it was able to ignite the gas line.

An investigation into a 1992 pier fire did not find a conclusive cause. But it did indicate that the electrical lines and gas lines did play a role in the blaze.