TORONTO — Peel police are treating a pre-dawn hallway fire at a Mississauga apartment tower as possible arson after a second blaze in less than 24 hours sent residents down ladders and as many as 18 people to hospital.Crews were called at 3:38 a.m. Monday to 920 Inverhouse Dr., near Lakeshore Rd. W. in Clarkson, and found fire in a third-floor hallway of the seven-storey building. Mississauga Fire Deputy Chief Ryan Baird said 16 people were rescued from third- and fourth-floor balconies with ladders and aerial trucks after a two-alarm response of 11 apparatus and about 43 firefighters. Peel paramedics later said 18 people were transported, two with serious but non-life-threatening burns; earlier police tallies had put hospital cases at 11, mostly smoke inhalation.An officer was taken to hospital with minor injuries that paramedics said were not caused by the fire itself, and a firefighter was also hurt. Acting Sgt. Amanda Steenson said a smaller fire had already started Sunday night on the same floor near a stairwell and was quickly knocked down. “We are looking at the possibility that the two incidents are connected,” she said, adding it is too early to confirm.Some residents were allowed back into their units once the flames were out. Inverhouse Dr. was closed at Lakeshore Rd. W. and Bonnymede Dr. while crews worked.No charges have been laid.