Conshohocken, Pa.—A construction site turned into an inferno on the evening of Aug. 13, burning two nearby apartment buildings to the ground and leaving hundreds of residents homeless.

"More than 300 firefighters from all corners of Montgomery County battled the spectacular fire, which raged for about six hours before crews got the upper hand about 10:30 p.m.," according to a story in the Philadelphia Inquirer.

The blaze began in a five-story wood-frame building under construction—Stables at Millennium—at 203 Washington St. and spread quickly across what one official called a "lumberyard" of construction materials to set fire to the apartment buildings nearby.

The Stables at Millennium are just one piece of Millennium, a 60-acre mix of offices, apartments, and shops developed on the banks of the Schuylkill River by O'Neill Properties Group, based in King of Prussia, Pa.

The fire at the Stables construction site spread to the Riverwalk at Millennium complex next door, which included four four-story buildings totaling 375 apartments owned by JPMorgan Chase & Co.

Two apartment buildings totaling 168 apartments were destroyed. No residents were hurt in the blaze, according to building manager Bozzuto Management Co. On Aug. 14, Bozzuto was still waiting to hear from fire officials whether the two remaining buildings at Riverwalk were safe to enter.

The fire burned so fiercely that two fire trucks operated by Conshohocken volunteers were overwhelmed by the flames and severely damaged. Officials have found no sign of arson at the site, according to local news reports.

The apartments at Riverwalk at Millennium had been almost fully occupied, with several unit types unavailable, renting at prices between $1.44 and $1.88 a square foot. Bozzuto is offering to move displaced residents to vacant apartments in other Bozzuto communities in the area, honoring their current lease terms and supplying these residents with basic furniture. Bozzuto is also working with the local apartment association to find residents new places to live.

"We want to make sure they all have both temporary and permanent places to live," said Bozzuto spokeswoman Lauren McDonald.