Officials say crews were battling a house fire Saturday in Fairfield when firefighters learned 200 pounds of lithium-ion batteries were in the garage.
Those batteries released fluoride gas when exposed to the fire and water.
"If people are experiencing any symptoms such as itchy throat, itchy skin, shortness of breath, and they were around this fire, exposed to this fire..they should immediately go to their nearest emergency room," said Sgt. Matt Bloesch.
Residents in the neighborhood were ordered to shelter-in-place during the firefight and hazmat situation.
The cause of the fire is under investigation.