The plant is shutdown and refinery officials are meeting with representatives from the Occupational Safety Hazard Administration and the Bay Area Air Quality Management District. They are all trying to figure out how the fire started.
The two-alarm fire at the Evergreen refinery in Newark woke up the neighborhood across the street. It was 5:30 in the morning -- residents were groggy and nervous.
"I heard a big boom and I was like 'what is that noise?' And my grandma was like 'did you hear that?' And I was like 'yeah.' Then I started hearing like all the police come and I was like 'wow.' And then we came outside and they said 'go back in your house because you may have to evacuate' and I was just like 'wow'" resident Vanessa Weaver.
There were 20 people working inside the plant when the fire happened. Two men were performing a routine task using a heat exchanger when their equipment failed. One of the workers hurt his arm, but is expected to be okay.
"We had an unexpected release from this equipment. The oil is supposed to stay in the exchanger for some reason it came out. And again right now we don't understand why that is," said plant manager Bob Gwaltney.
A worker inside the plant at the time of the fire tells ABC7 News the flames were huge and the situation was scary. The heat from the fire melted a fiberglass tank containing hydrochloric acid - which then spilled. Two hazmat teams came in to deal with the acid.
"That acid is all contained and those hazmat teams are in the process of cleaning that up," said Gwaltney.
Firefighters tested the water in a stream outside the plant for hazardous material and determined no chemicals leaked out of the plant. A crew spent the morning vacuuming the foam used to fight the fire out of the water.
This is the second fire at this refinery in less than a year. Last May, it took firefighters about two hours to contain a fire that started at 12:45 in the morning. No one was hurt.
The history of problems here has residents on edge.
"There's anxiety just like roaming around in the air. There was a crowd of 50 or 60 people earlier and they were really concerned about the issue," said resident Javier Sanchez.
"I'm scared I don't know what to think because one day we could be sleeping and our whole house is just going to explode," said Weaver.
"My focus is on today's incident, getting to the bottom of today's incident on verifying the condition of our injured employee and I'm really not prepared to speak about other incidents in the past," said Gwaltney.
OSHA has fined this refinery once before in 2007. OSHA was responding to a complaint and found 19 violations.