Mayor Eddie Francis told residents in the city's west end to stay indoors, close their windows and not use air conditioning after a recycling facility caught fire mid-afternoon.
Francis lifted the state of emergency at 9:30 p.m.
Health officials determined the air quality to be "acceptable and do not anticipate that changing through the night," a city-issued media release said. "Therefore the 'stay in place' request has been lifted.
A Windsor fire spokesperson said that at one point, 75 per cent of the nearly 57,000 kilograms (or 125,000 pounds) of plastic was burning at Sprucewood Industries, a plastic recycler in the 700 block of Sprucewood Avenue.
A huge plume of jet black smoke could be seen across Windsor and parts of Essex County.
"I was coming down the expressway and I saw this big black plume by Ojibway Park. When I got here, it was huge. It was like a bomb went off," said George Lucio, who lives near the scene. "I thought it was an explosion of some kind. It was just pitch black."
He and his wife Connie both described the smell of the smoke as "toxic."
"I closed all the windows, turned off the air and kept the dog in the house," Connie Lucio said. "We were concerned."
The John McGivney Children's Centre, more than five kilometres away from the fire, closed early and asked parents to pick up their children early due to what the centre called "poor air quality."
Dr. Allen Heimann, Medical Officer of Health with the Windsor Essex County Health Unit, said some individuals may experience irritation to the eyes and lungs from the smoke. He also said it’s best to stay indoors.
Windsor Fire and Rescue said the fire would burn until at least 9 p.m. ET but would keep firefighters on scene overnight. The structure was levelled by the blaze and transport trucks left melted in the parking lot.
Outdoor activities cancelled
The city closed all outdoor facilities in the aftermath of the blaze. The bedroom community LaSalle, Ont., also cancelled baseball games Tuesday night.
"Until we have a better sense of what … is happening, as a precautionary measure the city of Windsor will be closing all outdoor facilities for the day," he said. "So, anybody who had any events planned on the baseball diamonds, the soccer fields, with any events whatsoever, the city facilities will be closed."
Windsor Fire and Rescue said there were no reports of civilian injuries. One firefighter suffered what was called "a heat-related injury" but was expected to recover.
Nearly every firefighter and fire truck in Windsor responded to the incident. Neighbouring Tecumseh Fire and Rescue were put on standby and staged at Windsor's Station No. 7 during the fire.
Gawkers and rubberneckers flocked to the scene, shooting video and taking pictures with smartphones and cameras.
Windsor police closed the city's only expressway at 4 p.m., choking off east-west traffic during the busiest time of the day.
People living within 1.5 kilometres of the fire were told by police to "shelter in place."
People were advised to stay indoors with their windows close and air conditioning off. The temperature in Windsor was still 30 C at 7 p.m.
People did not have to evacuate the area, though Francis said those who felt uncomfortable, sick or unsafe indoors near the fire could head to cooling centres established at the Vollmer Recreational Complex in LaSalle and Mic Mac Park in Windsor's west end.
Fire officials at a media conference said the Sprucewood Industries facility has no safety violations on record. The plant was inspected by Windsor Fire and Rescue three years ago.
Windsor's Michael Evans shot the following video of the fire.