Manchester, NH - June 13. At 1245 hrs a full Box Alarm responce along with two RIT engines was dispatched to the Brady Sullivan hi-rise building at 1000 Elm Street for reported fire on the 21st floor. The fire was reported to be in the generator room, with reports that a catastrophic failure had occured and exploded spilling oil and fuel onto the floor and igniting. The fire quickly engulfed the generator and caused heavy smoke filling the 20th and 21st floors. Smoke also pushed its way down to the lobby through the open elevator shafts. A Second alarm was also transmitted due to the high rise building to be evacuated and also that the elevators were not working. Firefighters had to use the stairwells carrying there equip[ment to the 21st floor. During the ascent a firefighter had a minor medical emergency and was transported to a local hospital for evaluation. When crews reached the generator room, the fire was quickly extinguished and overhauled and ventilation was done on the 20th and 21st floors along with the lobby area. There were no other injuries and the building was evacuated safely.