A gas line operated by Pacific Gas and Electric Co. exploded yesterday, sending flames high into the air, the San Francisco Chronicle reported, adding that the explosion set five buildings around the line on fire. The explosion, it turned out, had occurred by accident, when a member of a Verizon crew working on the same street struck the gas line. It took the company two hours to put it out, the daily reports, because, as explained by a PG & E’s spokesman, the crew had to cut the asphalt to get to the line and turn off a valve to stop…