The Toronto District School Board is suing after a high school was destroyed by fire two years ago.
Legal documents show the board wants $90 million in damages from the city, province and police.
Its unproven statement of claim says the money is needed to rebuild York Memorial Collegiate Institute.
The board alleges firefighters failed to douse a small fire in the auditorium in May 2019.
It says the flames erupted again the next day, destroying the building.
The board says municipal and provincial officials had care of the building after the first fire and are responsible for damage from the second one.
TDSB interim director Karen Falconer says that the school board and its insurers had hoped to resolve the matter outside court but were left with no choice but to take legal action.