The Des Moines Fire Department says nearly half of the homes and businesses they respond to have smoke detectors that aren't working.
Fire fighters and volunteers set out to change that by visiting hundreds of homes in the Highland Park neighborhood Saturday.
A survey showed it was the area with the greatest need for smoke detectors in Des Moines.
Volunteers checked batteries and when necessary installed new smoke detectors.
Captain Steve Brown says when smoke detectors work properly they can be the difference between life and death.
"Those people are going to be outside. It's going to make our job that much easier. We don't have to go in and search for those people and use that time it takes to rescue someone. If people are out, we can go ahead and put the fire out and move on,” said Brown.
More than 300 volunteers participated in the installation blitz.