What happened at the aerospace manufacturing facility in Philadelphia and what is the current situation?

A massive fire broke out at SPS Technologies, an aerospace manufacturing facility north of Philadelphia, around 9:30pm local time. Witnesses reported explosions and flames engulfing the warehouse. Schools have been closed and residents ordered to shelter in place. Emergency responders are currently working to extinguish the blaze while monitoring air and water quality. Fortunately, all employees have been accounted for with no injuries reported. SPS Technologies is a developer and global supplier of aerospace fasteners and precision components.