Don't be alarmed if you see smoke drifting out of storm drains or sinks in downtown Knoxville on Thursday.
The city will be doing a smoke test. Crews will direct smoke into the stormwater system beneath the Clinch Avenue Viaduct.
The work is slated for 2 o'clock Thursday afternoon.
The city says any smoke you may see is harmless and will only last about 30 minutes.