Police were called to the washroom of the railway station on July 5 at around 11:15 p.m. for reports an unresponsive man.
In a statement released on Friday, the Special Investigations Unit said officers performed CPR on the man and administered naloxone before paramedics took over.
The 28-year-old man was later pronounced dead in hospital.
A cause of death has not been released, but naloxone is typically administered to reverse the effects of an overdose.
“The evidence is clear that none of the involved officers contributed to the man’s death in any way,” said SIU director Tony Loparco.
This is the second investigation the SIU has cleared in as many weeks in which a man died after naloxone was administered by Guelph police.
The oversight agency has been criticized for investigating incidents where police have administered naloxone to overdose victims.
The union representing provincial police officers in Ontario is calling on the SIU to end that practice.
In August, OPP Association president Rob Jamieson said there is a high level of concern among officers that they will “end up being the subject of an SIU investigation for simply doing their job and trying to save a life.”
The SIU has maintained that the arm’s-length agency is mandated under legislation to investigate incidents involving police where there has been a serious injury or death.
A spokesperson said to end the practice of investigating deaths where naloxone was administered by police officers would need a change to legislation.
— With files from the Canadian Press