Contingency firefighters covering the fire strike in South Yorkshire over the weekend were called out to Moorlands prison during the final period of industrial action.
They were alerted to a small fire at Moorlands open prison, Bawtry Road, Hatfield Woodhouse, Doncaster, when firefighters were striking between 10am and 3pm on Sunday.
The blaze was already out when crews arrived.
Contingency firefighters were also called to a fire in Wombwell Woods, Dovecliffe Road, Wombwell, Barnsley, during the same period of strike action.
Firefighters across the country walked out a number of times over the weekend as part of an on-going dispute with the Government over their pensions and job security as they get older.