Two inmates at the Elgin-Middlesex Detention Centre will soon be facing charges following a fire at the jail.
Fire crews and police were called around 9 p.m. Thursday after a mattress, bedding and papers inside a cell were set ablaze.
One guard sustained minor injuries.
Damage is pegged at $500.
London police say arson charges will be laid against two male inmates.
One of those inmates will also be charged with resisting arrest and assaulting a peace officer.