A report today from the chief of Emergency Management Ontario blames communications failures, procedural gaps and a lack of training for why it took 108 minutes to give an all clear.

Ontario Power Generation says there are normally between 100 and 200 orders per month.

Sylvia Jones, Ontario's solicitor general, said a "full investigation" has been launched to determine how the error happened.

"The alert was issued in error to the public during a routine training exercise being conducted by the Provincial Emergency Operations Centre," Sylvia Jones, the province's solicitor general, said in a statement.