PG&E detected a small leak in an underground gas pipeline in Palo Alto Thursday night.
No customers were impacted and the situation is safe, PG&E said.
A statement said PG&E "noticed a slow drop in pressure during a hydrostatic pressure test on Line 132 near Palo Alto ... We confirmed that the slow drop in pressure has the characteristics of a small pinhole leak of approximately one millimeter in diameter."
They have been working 24 hours a day to finish pipeline testing in Palo Alto before the cold Winter, when the demand for gas is expected to increase. PG&E said the purpose of testing is to find leaks just like this one. It should be easy to repair, but could take several days to complete.
On the pipeline where the leak was detected, more than 20,000 feet is made of 24-inch seamless pipe that was installed in 1947. Another 2,700 feet has a seam weld and was installed in 1957.
The pipeline that exploded in San Bruno last year was a 30-inch pipe with a seam weld installed in 1956. The 2010 explosion killed eight people and destroyed 38 homes.
Last month, a pipeline near Bakersfield that supplies gas to the Bay Area burst during a similar hydrostatic pressure test as the one in Palo Alto. The 34-inch pipe installed in 1950 was the first PG&E pipe to burst during testing.