At 2 p.m. on Wednesday, witnesses say you could see gas escaping up from the street, you could hear it hiss, and smell it as well. A contractor sawed through the pavement and ruptured a 10-inch gas main.
"When we happened to see the gas coming out, the first thing coming to my mind is what had happened to San Bruno," said Fernando Labra, a witness.
Workers and guests at The Donatello hotel and the J.W. Marriott were sheltered in place, an office building and the Academy of Art were evacuated, and traffic was stopped as PG&E eventually capped off the leak. And that's when the finger pointing started.
"The gas line was buried at 15 inches. The reason it wasn't down to 24 inches was it was protected with a steel plate. It had to go up and over a city facility in this case. The importance is that if there's no markings there, the work is not supposed to be done," said PG&E spokesperson Joe Molica.
PG&E says they hadn't marked the location of the gas line because the contractor, J. Flores Construction -- working for the San Francisco PUC -- wasn't supposed to excavate until Thursday.
"Yes, exactly and preliminarily that's what our investigation shows," said Molica.
"There's conflicting information about who's ultimately responsible. The contractor is saying that they weren't following lines. PG&E is saying that they hadn't gotten out here yet. That's all going to be part of the investigation as we wrap this up," said San Francisco PUC spokesperson Tyrone Jue.
Without gas, well-known restaurants near Union Square such as Morton's Steakhouse couldn't serve hot meals and in some cases closed up shop, sending employees home.
A lot of restaurants lost a lot of business. The good news is there were no explosions or injuries. Still, the investigation is underway.