RICHMOND -- More than 100 residents throughout Richmond reported a gas smell wafting through the air Tuesday afternoon, officials said, but the source of the smell was not determined.
The odor was first detected in Point Richmond, but reports came in from North Richmond, the Iron Triangle and along San Pablo Avenue, swamping the city's emergency call center, officials said.
Fire engines scoured city streets looking for the source as buildings in Marina Bay were evacuated and some Richmond schools briefly sheltered in place. But nothing was found.
"Based on the geography of the reports, we envision that this was a huge plume of some sort of gas that enveloped roughly half the city," said Richmond police Capt. Mark Gagan. "We were never able to locate the exact source."
Calls began pouring in at the emergency call center at 2 p.m., but about an hour later, the smell dissipated, and eventually officials called off the search, said Richmond Fire Battalion Chief Manly Moulton.
Fire crews responded to about three calls for people having difficulty breathing during that time, but it was unclear whether the calls were directly related to the gas smell, he said.
Richmond Fire Chief Michael Banks said it was possible an industrial facility had a liquefied petroleum gas leak, but that wasn't confirmed.
"The smell hit the city, and it was strong," Banks said.
Chevron officials issued a statement saying the Richmond refinery was not the source of the gas smell. The statement said the refinery's monitors did not indicate any gas leaks.
PG&E, too, said it was not the source, according to spokeswoman Tamar Sarkissian.
Managers at Shaper Lighting, a light fixture manufacturer in Marina Bay, evacuated all workers when the factory floor was overwhelmed with the smell of gas, workers said.
About 60 people stood outside on the sidewalk for more than an hour while the smell dissipated, returning to work at about 3 p.m.
A fire that sent a massive plume of smoke in the air at the Chevron refinery on Aug. 6, 2012, resulted in thousands of residents seeking medical treatment and lawsuits against the oil giant.
Staff writer Tom Lochner contributed to this report.