An investigation is underway into a massive weekend fire at a vacant, historic factory site Torrington—the second largest blaze in the city’s history, according to Torrington’s fire chief.

On Wednesday, demolition crews continued to tear down the damaged industrial buildings at the former Hendy Machine Company complex, a 7-acre property off Summer Street.

“It’s very sad,” said community member Robert Magyar as he watched the bricks fall.

“Very, very sad. To think—that’s Torrington’s history!” added his wife, Linda Magyar.

The couple has stopped by daily since Sunday, when a fire broke out just before 1 a.m. at what was once a city landmark.

“I couldn't believe what I was seeing!" Linda Magyar told News 12. “I grew up on Hoffman Street, which is right up here. This was always Hendy Hill, not Summer Street.”

“My dad was a foreman there in the '40s and '50s,” Robert Magyar said. “They were producing some fine equipment, some worldwide-known lathe machines and stuff like that. It was a proud part of Torrington.”

The fire spread quickly overnight, in part because of the old timber and chemicals there.

“Twenty-two departments in total were on scene throughout the next 24 hours, rotating aerial trucks. We had 12 aerial trucks, seven engines, a few rescue trucks—and from as far away as Sharon and New Milford and Avon and Simsbury all coming out to help,” Fire Chief David Tripp Jr. explained.

Tripp said it took crews three to four hours just to get the flames somewhat under control, estimating they used 2.25 million gallons of water.

The fire destroyed two of the empty buildings and seriously damaged a third, according to Tripp. But firefighters were able to spare the one business on site, Industrial Saws.

“We were able to save that building, and we're getting him back into operation probably within the next day,” Tripp told News 12. “I'm so proud of my department and the men and women and what they did and the effort they made to knock this down in one day and keep it contained.”

But firefighters remained there for days, including overnight, because of hotspots. One flared up late Tuesday afternoon as rubble was moved.

“The scene's been turned over to our fire marshal’s office, working with our police department,” Tripp explained, adding that a perimeter fence is going up around the property to protect it because of the ongoing investigation.

Sgt. Kyle Johnson said because of the immense size of the scene, it will be quite some time before investigators figure out the cause, but they're considering all possibilities including arson. They’re also reaching out to the public for any information about what occurred. A $2,500 reward is being offered by the state if a tip leads to an arrest.

Torrington’s mayor said the city is working with the governor’s office, state agencies and the Environmental Protection Agency to come up with a cleanup plan.

Anyone with information about the fire can call the Torrington Police Department Tip Line at 860-489-2065, the Torrington Fire Marshal’s Office at 860-489-2265 or the CT Arson Hotline at 1-800-842-7766.