A new spate of stabbings, overdoses and drug use in Australia’s immigration detention centres has put the Australian government in likely breach of laws designed to protect staff and detainees, internal documents show.

Earlier this year, Guardian Australia revealed catastrophic security failings across Australia’s onshore immigration network since Management and Training Corporation – a US private prison company used by Donald Trump to hold ICE detainees – won the $2.3bn detention contract in late 2024.

The federal government has repeatedly attempted to take a stick to MTC and its local subsidiary Secure Journeys to improve its performance, including through financial penalties and a fiery meeting last year between the home affairs minister, Tony Burke, and the company’s global president.

But new documents seen by the Guardian show serious security lapses have continued since, including through a spate of eight fire-related incidents at Villawood immigration detention centre and violence and drug use at Melbourne immigration detention centre (MIDC). Those failings have again put the department itself in the crosshairs of Comcare, the federal work safety regulator.

The documents reveal a string of incidents at MIDC involving violence, aggression, illicit substances and improvised weaponry since August. That includes a violent altercation on 18 August between two groups that led to six detainees being hospitalised for “slashing and stabbing injuries made using improvised weapons”.

On 10 September, a detainee was found overdosed in his room, requiring staff to administer Naloxone, a drug that reverses opioid overdose effects.

The incidents at MIDC prompted Comcare to warn the government that it was failing to control the rising number of “incidents of this type at MIDC and across the broader immigration detention network”. That failure meant it was likely to be in breach of the law, the document said.

“I have formed the reasonable belief that the department is contravening section 19 of the WHS Act by failing to ensure, so far as is reasonably practicable, the health and safety of workers and other persons,” Comcare said in its notice. “In particular, the risks associated with violence, aggression, and the presence of illicit substances and improvised weaponry are not being adequately managed.

“While the department has advised that a range of actions have been undertaken to address these risks, it has not sufficiently demonstrated that the control measures currently in place are effective in eliminating or minimising the risks, so far as is reasonably practicable.”

Comcare said the information available indicates these hazards pose an ongoing risk of serious harm to workers and others in the centres.

A separate Comcare document revealed that a series of eight fire-related incidents had taken place at Villawood immigration detention centre between February and May.

That’s despite prior warnings to government to intervene after previous fires lit inside Villawood exposed serious gaps in MTC’s preparedness. That includes one fire on 23 September 2025, when MTC staff rushed into a detainee’s room to save him from a fire without proper safety equipment, causing two workers to be hospitalised.

The regulator found the department had not conducted its own systematic review of “all fire and smoke control measures falling within its influence or control”, a likely breach of work health and safety regulations.

“The occurrence of multiple notifiable fire incidents over a period of approximately four months, particularly after previous regulatory intervention concerning substantially the same risk, provided repeated and compelling circumstances requiring the department to review the effectiveness of relevant control measures,” the Comcare document said.

The Guardian previously revealed a series of incidents across the centres since Secure Journey took over, including escapes, staff injuries and sick detainees missing medical appointments due to a lack of staff to escort them.

Lyndal Ryan, national president of the United Workers Union, which represents workers in the centres, said the notices from Comcare show “the continuing dangerous situations facing workers and detainees inside detention centres, and Secure Journeys’ inability or unwillingness to address those issues”.

The union has continually raised concerns about understaffing in the centres, and Ryan said Comcare has made it clear that the department has the responsibility to pull Secure Journeys into line.

“The list of eight fires at Villawood over a four-month period are signs of the instability and chaos our members are witnessing almost every day,” she said.

A spokesperson for MTC’s local subsidiary, Secure Journeys, said:

“In response to your questions, I can confirm that Secure Journeys’ commitment to maintaining safe and secure operations, as well as both staff and detainee welfare remains our top priority.”

The Australian Border Force was contacted for comment.