Extensive damage was caused to a sprayer unit within SDC Trailers on Good Friday afternoon.
Fire and Rescue Service crews from Magherafelt, Cookstown, Maghera, Antrim and Ballymena attended the blaze at the Deerpark Road near Toome, which was reported at 2.30pm.
Noone was injured in the fire, which is understood to be accident. The SDC building was evacuated while the fire was being dealt with.
A Fire and Rescue spokesperson said around 100,000 litres of paint were stored in the sprayer unit.
Two fire crews from Magherafelt were first to arrive at the scene and managed to contain the blaze. Due to low water pressure in the area a water carrier from Dungiven was called in.
Six Fire personnel entered the building wearing breathing apparatus and the blaze was under control within an hour. The spokesperson said there was also considerable smoke damage to the surrounding building.