Retail, Shopping Mall Arson fire extinguished by fire sprinkler (Lehigh Valley, PA) December 17, 2013 viking210 At about 3:44 a.m. on Sunday, December 15, a fire alarm was set off at the Carbon Plaza Mall. Fire crews who arrived at the scene found that the fire had already been eliminated by the building’s fire sprinkler system. Investigators report that the cause of the fire was likely arson, but no one was injured in the incident.