The fire was reported just after 4 a.m. Thursday in the concrete storage building where several vehicles and a boat used by the Scout Leader's Rescue Squad were stored.
Formed in 1930 after a deadly train wreck, the all-volunteer squad assists and supports municipal rescue personnel at emergency scenes. Much of the squad's equipment is purchased and maintained with United Way funds, as well as grants and money from the volunteers' own pockets.
Patrick Ryan of the Fire Department's Fire Prevention Bureau said firefighters found one of the building's garage doors open and flames shooting from one side of the building.
He said the cause remained under investigation.
A firewall between sections of the building helped contain the damage to the section where the Scout Leader's equipment was stored. City equipment is stored in another area.
''It certainly is a very large tragedy for the community,'' said Matt Haerter, a division chief for the Kenosha Fire Department.
The building served as a polling place for the city, and City Clerk-Treasurer Jean Morgan said voters would be informed the polls will be moved to a nearby school for the spring elections.