A trio of state and federal agencies on Wednesday descended on a Monmouth storage building a day after an explosive fire leveled it.

Officials from the Office of the State Fire Marshal and the Maine Department of Environmental Protection were both at the 235 South Monmouth Road chicken barn that AD Electric Inc., of Sabattus, used for storage. The Occupational Safety and Health Administration also was gearing up for an investigation because the fire injured an AD Electric employee.

The employee’s name and an update on his condition were unavailable Wednesday. The employee was taken by private vehicle to St. Mary’s Hospital in Lewiston. He was transferred later to Maine Medical Center in Portland with second- and third-degree burns.

No other injuries were reported from the acrid blaze Tuesday, which sent thick black smoke into the air and caused several thundering explosions that rained burning debris on the dry grass and brush surrounding the area.

David Madore, spokesman for the Maine DEP, said the immediate concern is cleaning up the area of potentially harmful chemicals. The DEP’s Emergency Response Team was on site shortly after the fire was extinguished.

Jeff Quinn, an AD Electric employee who was working at the building when the fire broke out, said Tuesday there were about 700 gallons of oil in the building.

Madore said the oil is the biggest concern.

Absorbent booms were visible Wednesday morning in a drainage ditch that ran in front of the property. Madore said crews would learn whether there are any other problem materials once they begin the cleanup.

“The DEP was on the site (Tuesday) afternoon and well into the evening,” Madore said. “Everyone seems to feel the only thing they’re looking at is oil.”

AD Electric has hired Massachusetts-based Clean Harbors to clean up the area, Madore said. Clean Harbors employees are expected to meet with DEP responders Thursday to review and plan a strategy. Madore said there is no reason to believe there has been a contamination that would affect neighboring property.

There will likely be another review once the cleanup is complete to ensure neighbors’ water is safe.

“There will be some evaluation as it’s going on and I’m assuming after,” Madore said.

While the DEP will investigate the debris field for harmful chemicals, OSHA officials will investigate whether the injured employee or the company violated federal safety standards.

Maryann Medeiros, OSHA’s area director, said the agency received a report of the workplace injury on Wednesday.

“We’re just in the initial phases of the investigation,” she said.

Medeiros didn’t know how long the investigation would take, but she said the agency has six months to bring action against the employer. She didn’t know whether AD Electric had been investigated before. A search of OSHA’s reports indicates that the company has been fined twice since 2005.

No estimate of damage to the property has been made yet. The fire was in a former chicken barn roughly 400 feet long and used for storage. AD Electric owner Andrew Deditch did not respond to a phone message Wednesday seeking comment.

Sgt. Kevin Grimes, of the fire marshal’s office, said investigators have determined that the fire was sparked by accident. The fire marshal’s investigation is largely complete.

“We have a couple more people we want to talk to just to put the finishing touches on it,” Grimes said.

The fire started around 3 p.m. Tuesday as an employee was using a bucket truck to weld the top of a temporary traffic light like those used at road construction sites.

“We’re not sure why yet, but a hydraulic line that raises and lowers the bucket let go, spraying hydraulic fluid,” Grimes said.

Sparks from the welding ignited the fluid, spreading fire to the truck and the building. The employee quickly lowered the bucket and jumped to safety, but not before being burned.

Crews from nine departments across the region, including Leeds, Bowdoinham, Sabattus, Litchfield and Wales, were called to help douse the fire, which was still burning more than two hours after it started.

Smoke from the fire was visible for miles around. The fire caused material inside the building to explode, causing several thundering explosions that echoed throughout the area.

Heat from the fire scorched trees and destroyed several trucks and cars parked outside. The heat melted the siding on a home across the road, some distance away.

Hot embers and flying debris from the fire and the ensuing explosions caused numerous brush fires in the grass and woods across the road. The flames, both in the building and on the ground, were fueled by a strong, gusty wind that blew across the fields that surround the area. Crews quickly extinguished the brush fires, preventing them from spreading to nearby homes.

Craig Crosby — 621-5642

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Twitter: @CraigCrosby4