Staff at Oberstown youth detention centre in Dublin will begin a series of work stoppages this morning over health and safety concerns.
Their unions, IMPACT and SIPTU, have said staff at the facility are exposed to daily risk of violent assault.
There were over 100 violent incidents at the centre last year, almost half of which were classed as “critical”, according to the unions.
Official figures for 2015 show critical assaults and injuries necessitated a total of 3,005 employee sick days, involving 65 staff members.
The campus in Lusk currently caters for 48 under-18s, including a mix of vulnerable young offenders and people with multiple convictions for serious offences.
The youths will be confined to their rooms for part of the day when workers take to picket lines from 8am.
IMPACT and SIPTU said full emergency cover is in place for the four-hour work stoppage and that no state exams at the facility will be disrupted.
Unions and management have been invited to talks at the Workplace Relations Commission tomorrow, but further strikes are still planned for each Tuesday in June.
IMPACT official Tom Hoare said policy decisions have left care workers "doing the work of prison staff with the facilities and equipment of a residential care home".
"The campus is badly designed, with inadequate safety equipment to deal with a mix of vulnerable young people and violent offenders," he said.
"The result is a daily risk of serious assault, which leaves many of the staff literally in fear of their lives as they leave for work each day."
Campus manager Pat Bergin told Newstalk that the strike will have a "significant impact" on residents, who will have to remain locked in their rooms until 12pm.
Measures will have to be put in place to ensure the young people receive food and water, he said.
Minister's response
Minister for Children and Youth Affairs Katherine Zappone also expressed regret at the decision of staff to engage in industrial action, which she said will impact on school attendance.
"Major advances have been achieved in the Oberstown campus in recent years, with significant capital investment in new children detention facilities, the first programme of recruitment for care staff in over 10 years and the establishment of dedicated cross-campus management," she said.
"The issues which are the subject of this dispute are best dealt with through a process of dialogue and agreement under the state's independent industrial relations machinery.
"I welcome the fact that staff representatives have agreed to engage with Oberstown management at the Workplace Relations Commission on Wednesday of this week.
"However, the fact that this engagement is happening means that, having regard to normal industrial relations practice and the Lansdowne Road Agreement, there is no basis for this industrial action to take place.
"I am concerned at the interruption that will result in the normal routines of children this morning, including their attendance at school on the campus with state examinations taking place within the next week".
The staff concerned work at three schools on the campus: Oberstown Boys School, Oberstown Girls School and Trinity House.
Responsibility for the centre was transferred from the Department of Justice to the Department of Children and Youth Affairs in 2012.
