Fire crews have been on scene for about 20 minutes and have detected some levels of CO on the first floor and in the basement. A crew on the roof has detected the same smell there and they are shutting down the heating/cooling system.

UPDATE 8:52 a.m.: City fire has cleared the building of CO and levels are down to zero.They have isolated the problem to the heating units on the roof and all of the heating and cooling units have been shut down until maintenance arrives. Engine 12 will remain on scene until they arrive.

UPDATE: 9:06 a.m.: Engine 12 has now cleared the scene and is back in service.