An east-end Toronto high school will remain closed for at least three more days after fire and plumes of thick smoke forced its evacuation last week, the Toronto District School Board said Monday.

Toronto police now say the three-alarm fire that shut down Danforth Collegiate and Technical Institute on Wednesday was arson.

The school has been closed since a fire was discovered in a storage closet on the school's first floor by students in a drama class.

The closure will continue until at least Thursday as students continue to report to either Eastern Commerce Collegiate Institute or Monarch Park Collegiate Institute on a reduced school schedule.

The decision came after a Toronto District School Board meeting Monday to discuss the next steps. It is still unclear when the school will reopen, though students will be allowed into the school on Thursday to retrieve their belongings from their lockers.

During the fire, heavy smoke billowed from the school, near Danforth Avenue and Donlands Avenue, before fire crews were able to knock out the blaze.

All 1,200 students and 160 faculty members evacuated the school safely, and a firefighter was treated at the scene for heat exhaustion.

The TDSB says they will not be able to assess the monetary costs of the fire until the police investigation concludes. A spokesman said students would not be allowed to return until the board could ensure their safety.

More information about the school closure, as well as a schedule for students to retrieve their belongings, is available at