MONTVILLE, Conn. (WTNH) — Fire crews worked to all morning to put out a large fire at a scrap yard in Montville.

Just after 1 a.m., firefighters were called to Connecticut Scrap at 33 Pequot Rd. to put out the flames.

Montville’s four Volunteer Fire Companies, along with Montville career staff firefighters, and mutual aid firefighters from area partner departments were called to the scene. Fifteen units were called in total.

Officials reported receiving more than 30 911 calls. Some even reported hearing what sounded like an explosion.

“There’s a possibility that there could be some empty propane tanks that were in there that may have caused some of the explosions that some of the neighbors heard,” said William Bundy, Montville Fire Marshal.

The Connecticut Department of Energy and Environmental Protection (DEEP) was also called to the scene to monitor the air quality in the surrounding area. People nearby were asked to keep their windows closed.

“DEEP has indicated that it [the air quality] is within an acceptable window,” said Bundy. “They will continue to monitor it. Certainly, residents in this area are encouraged to keep their windows closed. If there’s any debris in the area, certainly don’t touch it.”

DEEP staff report that light metals, vehicles, batteries and motor vehicle fluids — such as petroleum — burned in the fire, which was significant and very smoky.

Thousands of gallons of water were used on the fire, which was 95% contained at 9:45 a.m.

“DEEP staff performed Photo Ionization Detection to check the air for volatile organic compounds,” DEEP spokesman, Will Healey, told News 8. “Staff reported that the readings were very low.”

If residents are concerned about smoke, they’re advised to contact their local health department for further directions.

DEEP staff will remain on scene Friday and Saturday to gather information.

No injuries have been reported.

The case of the fire has yet to be determined. It is being investigated by the State Fire Marshal and the Montville Fire Department.

Bundy said it’s too soon to say if the early stages of drought played a roll. 

“As we get into the investigation component of it, it’s something we will look at.”