One person has died after being exposed to carbon monoxide in the underground garage of a Scarborough, Ont., highrise, police said Wednesday. 

Three others were transported to hospital with minor injuries, all due to carbon monoxide exposure, after police received the call around 2 p.m. ET. 

The male victim, who has not yet been identified by police, was reportedly without vital signs at the scene and was pronounced dead in hospital after arriving. 

According to Toronto EMS, four people were using gas power washers to clean the garage floor when one of the workers lost consciousness. 

The first six storeys of the building at 15 Torrance Road were evacuated for about two hours as emergency crews ventilated the complex.

"We found extremely high levels in the lower floors of the building and the basement area. It took quite a while for us to ventilate that, to bring the atmosphere in the building up to a healthy breathing level," said Capt. Stephan Powell with Toronto Fire Services.

Ministry of Labour investigators remained on scene well into the evening. 

TTC buses were used to provide shelter for people forced out of their homes during the evacuation. 

Toronto EMS also responded to another carbon monoxide poisoning incident at around 7:45 p.m. near Markham Road and Sheppard Avenue in Scarborough, where a 20-year-old male was transported to hospital with non-life threatening injuries. 

It is reported that the male was also using a gas power washer at the time.