San Francisco Chronicle

A scary blast in a busy city

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Constant constructi­on is a fact of life in San Francisco, putting up huge high-rises, chewing up roads and, surprising­ly, blowing up buildings. A 40-foot tower of flame burned for hours, incinerati­ng a corner restaurant and nearby apartments on a busy street in the Inner Richmond District.

Onlookers were astonished at the wall of fire Wednesday. Firefighte­rs were relieved to report no one was injured among a ditch digging crew that apparently pierced a gas line while laying down fiber optic line. But the rest of the city must wonder if such a blast, so easily created, could happen again with a far greater toll.

Think of an earthquake, stormcause­d washout or another excavation mishap. San Francisco is crisscross­ed by undergroun­d gas lines that residents count on for safe service. It’s also a busy, regenerati­ng city where ripping up pavement is a necessity.

There are safety procedures when digging near such lines, though the rules didn’t help this time. A National Transporta­tion Safety Board team of federal investigat­ors is due to examine the accident and could provide an objective reading of what went wrong. An initial account suggests the private firm installing the undergroun­d cables was the starting point.

But that explanatio­n doesn’t end it. An obvious concern is the delay of over two hours it took until Pacific Gas and Electric crews could find a nearby valve and shut off the gas feeding the fire.

That task needed hand-shovel work that took precious time, because heavy constructi­on equipment could cause extra damage. A utility spokesman added that shutting off lines isn’t lightly done because of inconvenie­nce it causes other customers.

It’s not hard to draw a comparison with the 2010 San Bruno blast which occurred when a flawed pipeline broke and exploded, killing eight and flattening a neighborho­od. Gas-fed flames burned for 90 minutes until a shut-off valve was found, but fires lasted longer because waterlines needed by firefighte­rs were cracked by the explosion.

San Francisco — and the rest of PG&E’s half-state service area— needs to be assured that there’s a reliable and prompt way to shut off flammable gas leaks. The giant utility is already facing rightful criticism and serious legal penalties amid pressure to improve its safety policies connected to open-country wildfires. One option advanced by the utility is massive shutoff over a wide area when wildfire conditions loom. It’s a major expansion of prior practices that cut power via intentiona­l blackouts, but it can also penalize customers who live far from the danger zone.

The San Francisco blaze adds another concern to this list of worries. The utility’s practices in a tightpacke­d city are just as important as fixing its empire of wires and towers in rural spots. A safe way to control fire risks needs to be a priority.

 ?? Santiago Mejia / The Chronicle ?? Firefighte­rs battle shooting flames after a gas-line explosion at Geary Boulevard and Parker Avenue, as PG&E workers dig up the ground with hand shovels to reach the damaged pipe Wednesday.
Santiago Mejia / The Chronicle Firefighte­rs battle shooting flames after a gas-line explosion at Geary Boulevard and Parker Avenue, as PG&E workers dig up the ground with hand shovels to reach the damaged pipe Wednesday.

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