The fire began around 1:55 p.m., Thursday, Dec. 17, at the Pilot Travel Center on Old Gate Lane in Milford, said the Milford Fire Department.
Responding firefighters found two tractor-trailers on fire and two other trailers nearby.
The diesel fuel in the trucks was also involved in the fire.
Crews pulled numerous fire hoses and used foam to stop the fire from spreading and to extinguish it, the fire department said.
One of the trailers contained boxed vegetables, and the other held over 4,000 pounds of bleach.
One of the fire hydrants near the scene was found to be inoperable, and crews needed to lay an additional 800 feet of hose to a second fire hydrant.
One firefighter was transported to Milford Hospital by the Milford Fire Paramedics in stable condition.
The cause of the fire is under investigation.
Click here to follow Daily Voice Wilton and receive free news updates.