Crews rushed to Hallens Drive, near to the Wednesbury Parkway tram stop, to the blaze at the former 24/7 Fitness gym on Wednesday.
Seven fire engines were sent to the scene at around 2.40pm to fight the blaze at a two-storey building which was extinguished at 5.21pm.
West Midlands Fire Service said electricity to the building was isolated so crews could work safely, which also impacted around 40 homes.
Meanwhile residents nearby were advised to keep their windows closed as metro services imposed speed restrictions on the nearby route.
The building, which sits across the road from a branch of Dreams, the mattress shop, has been vacant since 24/7 Fitness closed earlier this year citing the "financial impact of Covid!.