RICHMOND -- Toxins and pollutants were at a "good-to-moderate" range after Monday's Chevron refinery fire, air quality regulators said.
Though hundreds of residents were treated at nearby hospitals for reported respiratory problems and vomiting, air samples taken throughout the region showed toxins at relatively safe levels even during the hours-long blaze, Bay Area Air Quality Management District spokeswoman Kristine Roselius said.
Weather conditions during the fire had been just about ideal, said the BAAQMD's director of technical services, Eric Stevenson.
Winds close to the ground were very low, allowing the smoke to rise thousands of feet into the air, where higher winds began blowing it eastward, he said.
The result was that most of the smoke didn't end up touching down on nearby communities, but was instead blown into the Central Valley and the Sierra Nevada, Stevenson said.
"We all recognize this incident created a lot of black smoke, and had impacts not dissimilar to a wildfire, something like that, that produces a lot of particulate matter," Stevenson said. But with respect to the toxins actually released into the surrounding communities, he said, the impact was comparable to standing on a sidewalk near the exhaust from passing traffic.
"The impacts were not dissimilar to what we see on a day-to-day basis," he said.
Asked about the apparent disconnect between that conclusion and the hundreds of people who reported being made sick by the smoke, Stevenson said:
"People were feeling something. We're not saying nothing was out there. That's what we're trying to ascertain today, with additional analysis."
It's also possible, Stevenson said, that tests weren't taken in the areas most affected by the smoke. Samples were taken where the most smoke was reported, but it's possible smoke was underreported in the neighborhoods most affected.
A Spare the Air Day is expected to be called Thursday and possibly again on Friday, but for reasons unrelated to the fire, Roselius said.
The Contra Costa County Health Services tests which track hydrogen sulfate and volatile organic compounds both came up negative, said a health services spokeswoman.
The three-alarm fire broke out at about 6:30 p.m. and was burning strong before it was contained just before 11 p.m.
More than 500 people -- more than 300 at Doctors Medical Center in San Pablo and 200-plus at Kaiser Permanente in Richmond -- were treated for respiratory issues.
Bay City News contributed to this report. Contact Sean Maher at 925-943-8013. Follow him on Twitter at twitter.com/OneSeanMaher.
By Sean Maher Contra Costa Times