04/20 - Kuhl Hose was dispatched to assist Lawrence Park at the G.E. with RIT after a reported building fire.  Dispatch reports were some type of fire at Building 18.  Lawrence Park arrived and found a fire in the stack system on top of building 18.  Once crews arrived at the location of the fire it was determined that welding sparks set fire to filters in the stack system.  Initial attempts were made with dry chem extinguishers to contain the fire without success.  Crews stretched line to the fire from the 2nd division roof and used Ladder 249 waterway as a standpipe.   The fire was quickly contained.  683 RIT split and monitored 2 sides of the building as well as from the 2nd division roof.  RIT remained on the scene until the fire was contained and all crews were clear of the roof.