An explosion occurred around 2 p.m. Monday at a San Diego hotel construction site. 14 workers were injured, 5 of which were in critical condition. Although authorities haven’t made an official report, they said that the cause was, most likely, a gas leakage.

According to The Associated Press, the explosion damaged a part of the Hilton hotel’s façade and sent out debris on a driveway.

People who were around the area, initially thought that a bomb exploded as there was just smoke.

“It looked like a bomb. It shook the whole building like a bomb,” said Matt McBride, general manager of a bar located about 150 yards away from the site, reported The Associated Press.

Perry Peake, San Diego Deputy Fire-Rescue Chief, said that the explosion happened in a part of the building which contained gas and electric utilities.

Some of the victims were transported to the UCSD Medical Center and 3 of the 5 critically injured workers were in the burn unit as they had burns that covered up to 35 percent of their bodies.

Hospital spokeswoman Kimberly Edwards said Monday evening that six of the workers from UCSD had been released, one was in a stable condition and the 3 burned workers were in induced comas.

As for the building, it didn’t burn, but suffered serious damage.

The Hilton San Diego Bayfront hotel was scheduled to open in December. According to The Associated Press, there were about 400 workers inside the building at the time of the explosion.