A fire caused $400,000 in damages at a commercial building on Gladstone Avenue.
Officials say the investigation is complete and the cause is listed as undetermined.
Windsor firefighters were called in to deal with a major fire at Nunes Building Maintenance at 1574 Gladstone on Tuesday.
At various points, additional firefighters had to be called in, and crews could be seen wielding chainsaws as they attempted to access the fire.
Windsor Fire & Rescue Service officials were asking people to avoid the area due to the possible involvement of chemicals and a hazmat team was being called in as a precaution.
Fumes were reportedly very strong at the rear of the building and Windsor police were called in to move people further away from the area.
There was reportedly no one inside when the fire broke out.
