LA CROSSE, WI (WKBT) -

A potentially life-threatening situation was avoided in downtown La Crosse Wednesday and it was thanks in part to a simple device.

Firefighters were called to the 300 block of Main Street around 7:30 p.m. for a report of high carbon monoxide levels.

The building houses businesses and apartments.

Firefighters found a malfunctioning furnace causing the high gas readings.

There were no medical problems reported. "Obviously if it would have been for a long period of time there could of been problems, but here was a case where a carbon monoxide detector was the first indicator that there was a problem, the tenant recognized that and called 911 and everything worked out," said La Crosse Fire Dept. Div. Chief Tom Wallerich.

One resident was displaced for the night.