A 3-inch natural gas pipeline was ruptured by a construction crew digging near Mission Bell Drive and Castro Road at about 10:10 a.m., PG&E spokeswoman Tamar Sarkissian said.
PG&E workers responded and have isolated the leak and stopped the flow of gas to the line, Sarkissian said.
No one was injured.
Natural gas service has been interrupted to about six buildings on the Contra Costa College campus while crews repair the pipe, Sarkissian said.
Service is expected to be restored sometime this afternoon.