PG&E identifies mystery odor during pipeline check

August 2, 2011 7:16:50 PM PDT
A disconcerting odor in San Bruno has put the brakes on a PG&E project Tuesday afternoon. Crews were trying to do a video inspection of an old abandoned pipeline when the strong smell of gas permeated the neighborhood. PG&E says it's harmless, but it took them until about 6 p.m. to figure out what it was.

Crews were on standby all day waiting for the odor to be identified since it prevented them from launching the video inspection. Shortly before 6 p.m. PG&E said the smell was from hydrocarbons -- minute traces of natural gas which they say is harmless. After the smell was identified, crews were able to put the robotic camera into the pipeline.

PG&E is using what it calls a robotic crawler equipped with a high definition camera. Workers lowered it into a hole Tuesday morning where two non-working sections of Line 132 -- the pipeline that ruptured Sept. 8th -- are now exposed.

The camera will go into a third pipe which runs right next to Line 132. It's a line which has not been used for five decades.

The California Public Utilities Commission ordered the inspection as part of its investigation into last fall's natural gas line explosion. PG&E started last Thursday and late Friday removed an eight-foot section. But on Saturday when they were about to put that camera into the abandoned pipe, the crew and neighbors smelled a strong odor and work was stopped.

"We took readings of the pipe and we picked up trace amounts of natural gas. Initially, we thought the odor was mercaptan, residual mercaptan left over in the pipe," said PG&E spokesman Brian Swanson.

Mercaptan is a chemical that's added to odorless natural gas to create a smell that's detectable. Tuesday, the utility sent its workers door to door in the immediate neighborhood, notifying residents that they might smell mercaptan again when work resumed. When they opened the pipeline late Tuesday morning, an odor filled the air once again. PG&E now tells us that the smell noticed on Saturday and Tuesday is not mercaptan.

Regardless, neighbors are documenting everything just in case it turns out to be something serious. The elderly resident of one house is on oxygen. Her daughter says she smelled the odor Saturday.

"I wonder... she's been sick since Sunday night and I came because it was getting bad. I wonder if that had anything to do with how she's feeling?" said San Bruno resident Vula Brown.

The camera is supposed to inspect 250 feet of pipeline.


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