Victorian police officers' prolific use of pepper spray escalated incidents and increased the risk of harm to people, a review by the state's anti-corruption watchdog has found.
In a 2021 incident, police responding to a protest against COVID-19 restrictions in a regional town approached a person to ask what they were doing in the area, to which the person requested to see the officer's ID.
A back and forth ensued before a sergeant took the person to the ground and attempted to handcuff them while they fought back asking to be treated respectfully.
The officers warned the person and used pepper spray to their face before dragging them to a van and striking them with a baton when they refused to put their feet inside.
The person was held in police custody for more than 24 hours, their next of kin was not notified and they had to be treated in hospital for multiple injuries.
Officers charged the person with a slew of offences including assaulting and resisting police and failing to follow orders, despite not interviewing them first.
The person lodged a complaint alleging multiple police failures including excessive force, unlawful arrest and wrongful bail conditions, but the force's investigation only considered the excessive force allegations and found it unsubstantiated.
The Independent Broad-based Anti-corruption Commission reviewed 15 investigations conducted by the force involving officers using pepper spray between January 2020 and March 2022.
It examined the interactions, aftercare provided after OC spray was used, and the quality of subsequent internal Victoria Police investigations.
The body identified issues with all 15 investigations and found nine investigations were "not of the expected standard".
Despite the Victoria Police manual directing OC spray should only be used on reasonable grounds and not when a person is "only passively resisting", IBAC found some officers considered the spray a low-level use of force.
In many cases the decisions and actions of police "escalated incidents or increased the safety risk" of those involved, the watchdog said.
The review also found, that in some incidents, police did not provide a verbal warning before using the spray and aftercare was often not given to those impacted.
Human rights were not considered and police did not consider the potential for physical and psychological harm when deploying the spray during some incidents, the watchdog found.
IBAC said investigations into incidents involving OC spray were "not rigorous" and Victoria Police failed to impose serious disciplinary action when allegations of misuse were substantiated.
The anti-corruption body made several recommendations to Victoria Police following the review including, regular refresher training on the appropriate and safe use of OC spray, updating official advice on psychological and physical injuries and verbal warnings, and developing a step-by-step guide for administering aftercare.
Victoria Police has partially accepted four recommendations and two in full.
Police have updated training around psychological and physical injuries from pepper spray and now require all frontline units to carry water for aftercare, a spokesman said.
"In an ideal world police would never need to deploy OC spray but the reality is there are instances where it is necessary to de-escalate conflict and keep the community and police safe," he said.
The review has been shared with the force's Professional Standards Command to ensure rigorous monitoring of any active investigations.