A fire broke out shortly after 10:00 pm, Sunday, at a Bucks County apartment complex.

The blaze was confined to one building at the Windsor at Harper’s Crossing apartments near Route 1 and I-95 in Middletown Township.  Three firefighters were treated at Saint Mary Medical Center for smoke inhalation or heat exhaustion, and about 20 residents may have been displaced.

The cause is under investigation, but it could have been a lightning strike.