A fire has broken out at the Oberstown youth detention centre in Co Dublin.
Five units from the fire brigade are attending the scene, along with the environmental unit, which contains heavy duty water cannon.
Earlier this evening, several teenage detainees staged a rooftop demonstration at the facility.
The demonstration followed an eight-hour work stoppage by staff protesting against working conditions.
Some of the residential care workers staging the protest came off the picket line to deal with the incident.
Meanwhile, SIPTU and IMPACT trade unions said the new expanded campus is badly designed to deal with vulnerable young people and violent offenders.
Attempts to resolve the dispute at the Work Relations Commission have so far proved unsuccessful.
The unions have served notice for three further stoppages next month on 5, 12 and 19 September.
Speaking on RTÉ’s News at One, Oberstown director Pat Bergin said some staff "from the picket line have come to assist in relation to a number of different matters" since the action began this morning.
Minister for Children and Youth Affairs, Katherine Zappone said she regretted industrial action was being taken at the centre.
"I understand that an agreement was reached by both sides just last Sunday (21st August) and I would have expected the protocols agreed under that process to be used," she said.
Ms Zappone called on unions to cancel the industrial action and utilise the mechanisms provided to address their concerns.
Management at Oberstown said "skeleton/emergency cover is in place" during the stoppage which began at 8am and ran until 4pm.
They also said, in a statement, that "Management have and will continue to utilise the work relations mechanisms of the WRC and the agreement reached on the 21st August 2016 framework to resolve this and other outstanding matters.
"Management call on Impact to withdraw the industrial action and to utilise the industrial mechanisms in place at the WRC to resolve the dispute."