About 40 firefighters responded to the call in the trailers behind the high school Tuesday afternoon.
A fire that damaged two classroom trailers at Phillipsburg High School on Tuesday was caused by a faulty electrical cord, a fire official said.
Investigators declared the fire accidental and electrical in nature, said Phillipsburg Fire Chief Rich Hay.
About 40 firefighters responded to the call about 4:30 p.m. after a smoke alarm activated, Hay said.
Firefighters had the blaze under control in minutes, but not before it caused significant damage to trailers 20 and 21 on the southern side of the school campus, near the auditorium.
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The trailers held two classrooms and weren't in use at the time, Hay said.
It will be up to the school district and its insurance carrier to determine the extent of the damages, Hay said.
"They're currently not in use and utility services have been disconnected," Hay said Wednesday morning.
Schools Superintendent George Chando said the trailers were used for small group instruction and general classes. Officials reassigned the classes into other space, he said.
"We just have to shift things around within the school building or within the other trailers," he said. An insurance adjuster had yet to issue an assessment, he said.
The power cord that started the fire was in a corner of trailer 20, Hay said. No injuries were reported.
Jim Deegan may be reached at jdeegan@lehighvalleylive.com. Follow him on Twitter @jim_deegan. Find lehighvalleylive on Facebook.