The review said it was a "damning indictment" that the prisoners involved in the May 2021 incident had spent most of the day with nothing to do and it was a "concern" detainees had easy access to homebrew alcohol.

"Of even more concern is that detainees do not have opportunities to fill their days with purposeful activities that will help prepare them for release," the report said.

The review found there had been "unsatisfactory" progress on the emergency management framework review required after a November 2020 riot in the prison, and the lessons from the riot had not resulted in changes to procedures.

Guards used pepper spray in response to the incident for the first time in the Alexander Maconochie Centre's history, which the review by the Independent Inspector of Corrections found was appropriate, but noted it was an issue the prison did not have policies or procedures in place to govern its use.

"The emergency management response to this incident appears to have been managed better overall compared to the only comparable previous experience in AMC's history, the riot in November 2020," the review found.

"Concerningly, however, many of the issues raised by staff after this incident were also raised back in November 2020. Recommendations made by this office in relation to that incident were accepted by government, but many remain in progress."

The report found the lack of structured day for detainees meant the entire unit had little to do and was "undoubtedly a contributing factor to the disturbance", but the post-incident assessment process represented good practice.

"That 35 of the 37 of the unit residents remained in their unit during the day when this incident 'kicked off' is a damming indictment about the lack of a structured day at AMC," the report, written by Neil McAllister, said.

"These detainees should have been engaged in activity around the AMC such as gaining skills in industries, participating in education, engaging in programs, recreation, or other activities. Instead, they were sitting around with nothing to do."

The report made four recommendations, including calling for a review and update of the emergency management framework within the prison and that the evacuation of detainees in case of a disturbance involving fire is included in training scenarios.

ACT Corrective Services staff did not feel adequately trained or prepared to intervene in the situation earlier, the review found.

Guards found several detainees on May 12, 2021 in a two-storey unit showing signs of intoxication, with prison staff forming the view detainees were intoxicated on "homebrew", which they were drinking from a plastic tub.

Between 3 and 4pm that afternoon, fights began to break out between the detainees and two prisoners became aggressive with officers, making threats and verbally abusing the prison staff.

"At this time officers withdrew their presence from the common area and secured themselves within the Officers Station," the review said.

"The two main instigators made attempts to break in to the Officers Station by throwing items from the unit kitchen and detainees' cells and kicking and punching the panels and windows of the office. Officers continued attempts to negotiate with the detainees, with no success."

Corrections officers called a full centre lock in, and 25 officers were called in about 4.30pm ahead of a planned operation to enter the two-storey unit and take control of the situation.

"Staff involved in this operation raised concerns for their safety given that there were 27 unsecured detainees still roaming in the unit and the aggressive nature of a number of the detainees," the report said.

"It was agreed between the Forward Commander and the Incident Commander that at this time it was too dangerous for staff to enter the unit and this operation was stood down."

Prisoners then kicked through the side panels and windows of the officers' station office, which was set on fire about 6pm and "quickly became engulfed in flames". A "Code Red" was called at 6.05pm.

Prison staff successfully used pepper spray to push back two detainees who attempted to interfere with an effort to extinguish the fire.

The original fire was put out, but detainees set fire to a cell on the lower level of the unit about 6.23pm, by using clothing and bedding to ignite the mattresses. Firefighters did not enter the unit, but the fire was put out using external fire extinguishers and cutting through mesh to push through a hose.

MORE A.C.T. POLITICS NEWS:

Detainees locked in their cells reported smoke, placing calls to the prison's master control room to make comments that included "open the doors", "we can't breathe" and "you're leaving us here to die". They were evacuated about 6.45pm.

"In the external yard, a number of detainees continued to cause damage to cameras and set fire to gym equipment. These fires were quickly extinguished by officers using fire hoses through the external steel mesh fence," the report said.

Negotiations continued with remaining detainees outside the unit, where they had been directed to move to so others in the cells could be evacuated. They were eventually assessed by health staff, strip searched and relocated elsewhere in the prison between 10.20pm and midnight.

The incident review, tabled in the Legislative Assembly on Thursday afternoon, noted the remediation work after the incident would take six months and was due for completion this month.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: