OAKLAND -- Two 20-foot sections of copper wiring were stolen from BART tracks Tuesday, increasing the agency's total 2011 copper theft loss to more than $90,000, a BART official said.

At 3:53 a.m., a BART employee noticed the theft, which occurred on tracks near Washington Street, between the West Oakland and 12th Street-City Center stations, BART spokesman Jim Allison said.

It was the third such burglary on BART tracks since Friday, and one of many in 2011, Allison said.

No arrests have been made but police have targeted at least one suspect and a few other persons of interest, BART police Deputy Chief Benson Fairow said.

Fairow said it is unlikely that the burglaries were an inside job by a BART employee, but he would not rule it out.

Police did not provide a suspect description.

The track burglaries have not interrupted daily service, but they have strained the transit agency's electrical system, Allison said.

Also, the repeated crimes are dangerous for the burglars, who risk electrocution or being hit by a train.

BART has incurred labor costs in addition to the price of lost supplies, as crews sometimes must spend more than one shift to replace the wire, he said.

"This is a theft from the taxpayers," BART board director Robert Raburn said, noting that tax dollars pay for stolen goods and repairs.

BART's most costly copper theft occurred in the summer in a Pleasant Hill yard, where burglars stole a spool of cable set to be used for a construction project in Contra Costa County, Raburn said.

That project has been delayed because of the theft, he said.

BART officials on Tuesday called for authorities to place more accountability on scrap metal yards, which buy the copper wire for $3 to $4 per pound.

"If people weren't buying it, people wouldn't be stealing it," Allison said.

Contact Chris De Benedetti at 510-353-7011. Follow him at Twitter.com/cdebenedetti.