The Vermont State Police are investigating the second arson fire in two days at the Chittenden Regional Correctional Facility in South Burlington.
Firefighters were called to the jail at about 5:20 Saturday afternoon after receiving a report of a mattress fire in a detention cell.
Police say the fire was deliberately set.
On Thursday, correctional officers extinguished a fire in a cell. That fire was also deliberately set. An officer received minor injuries putting it out.
Police haven’t said if they believe the two fires are connected.
No inmates were injured and no arrests have been made in either fire.