Residents of Thorold, Ont. are being told to stay indoors and close their windows after a massive fire broke out on Tuesday. According to Niagara police, the fire started just after 3:20 p.m. on Tuesday at Merit Auto Centre. Police said the building was fully engulfed in flames and there were small explosions coming from the building. "There is a large smoke cloud," police said. "Please stay indoors. Close your windows." Nearby buildings have been evacuated and roads in the area have been blocked off. Police said there do not appear to be any injuries reported at this time. Thorold, Ont. is located west of Niagara Falls on the Niagara Escarpment.