It also notes that a utility worker traced the leak to a valve in a meter set in the basement boiler room. Two residents and an employee were killed and about 20 people injured, including one of the utility workers, just a few days before Christmas. Part of the building collapsed, trapping people inside, as emergency workers, staff and even medics from a nearby hospital rushed to evacuate people. The Exelon energy technician determined there was a leak on a meter set valve in the basement and called for help fixing it. A meter set includes the meter, regulator, piping, valves and fittings.