The chemicals, and a large number of weapons and explosive devices, were discovered inside a house at 16-25 Bronson Road in Fairfield Tuesday afternoon.
Police, fire, Fairfield County HazMat, the FBI and other agencies are all working to make sure the area is safe.
The house belongs to Joseph Callahan, who called police Monday reporting a burglary. There was no sign of a break-in, but police say the 69-year old was behaving erratically. He was taken to a hospital for evaluation while police worked to make sure the neighborhood was safe.
During questioning, Callahan revealed he had large amounts of chemicals. A chlorine-based chemical inside the man's home caused breathing difficulties for one of the officers, which prompted the HazMat situation.
"There's no indication he was working on the chemicals," Fairfield Police Chief Gary MacNamara said. "There is no indication he was sick as a result of the chemicals. It appears initially that these chemicals, right now as they are, are stable."
The process has gone on for hours, and it may take days to clear the entire house.
Police say they found found hundreds of firearms and tens of thousands of rounds of ammunition.
Callahan's LinkedIn page describes a long career as a chemical engineer with Remington Arms. He appears in an undated photo with a rifle. Police say Callahan builds rockets as a hobby, and is also described as having a background in chemistry, but pjolice say that doesn't quite explain the explosives, and add that the activity at the home crossed the line into criminal behavior.
"Once the scene is rendered safe or evaluates to be safe, then we will be able to get in," assistant fire chief Chris Tracy said. "And the Fairfield County HazMat team will be able to evaluate the nature of the chemicals, and hopefully have the road cleared by morning."
The area is stabilized and there are some residents inside their homes nearby.
Police say they are still working to identify all of the chemicals inside the home. They've identified 12 so far.