Around 3:40 pm on Wednesday, December 1, 2021, as the last companies were returning to service from the Washington Ave fire, a call came in reporting a structure fire a few blocks away in the 1500 block of Iranistan Ave. This Charlie-6 assignment consisted of Engine 3, Engine 4, Engine 12, Engine 7 as RIT, Ladder 5, Ladder 11, Rescue 5, Safety Officer 1, and both Battalions. Engine 4 and Battalion 1 arrived on scene ans reported a small fire in a vent fan, which was quickly extinguished soon afterwards. FM-8 and Car 3 also responded to this incident. This was not a working fire. There were no injuries or need for relocations. The fire marshal's office is investigating the cause.