Dramatic video shows a freight train in Canada surrounded by wildfire flames and workers calling for emergency rescue as they report they are “engulfed” in fire.

“This could potentially hit us here, this has gotten a little scary,” says a crew member as the train passes burning trees near Armstrong, Ontario.

There are more than 100 wildfires in the province and several communities in the northwest are threatened. Smoke covered Toronto, which woke up to hazy skies and some of the worst air quality in the world.

The wildfires have raised concerns that smoke will reach American cities in the coming days, including New Jersey, where Sunday’s World Cup final will be held.

Canadian National Rail said in a statement that all workers trapped outside Armstrong were safely rescued and operations were temporarily suspended in the region.

The statement did not add more details about how the rescue occurred.

There are currently 838 active wildfires across Canada, according to the Canadian Interagency Wildfire Centre.

Grand Council Chief Linda Debassige said in a statement Wednesday that the remote Namaygoosisagagun First Nation in northern Ontario was “devastated by an unexpected and rapidly evolving wildfire” that severely damaged homes and community buildings.

More than a dozen fires are also burning in Minnesota, a US state on the border with Canada, due to extreme heat, dry conditions and strong winds.

Authorities have warned people to stay indoors to avoid smoke and to avoid strenuous activity and heavy breathing when spending time outdoors.

On Wednesday, residents of Canada’s largest city, which has also faced extreme heat this week, woke up to yellow skies and warnings from Toronto officials about dangerous air quality.

IQAir, a company that tracks global air quality, ranked it as the worst air quality in the world.

It ranked ahead of Kinshasa in the Democratic Republic of the Congo, Delhi, Dubai and Jerusalem.

Outdoor events for World Cup fans for Wednesday’s England-Argentina match were canceled in the city and children’s pools were closed.

In the United States, officials have warned that smoke is expected to reach the region starting Wednesday, even as extreme heat begins to subside.

Extreme heat warnings in the Midwestern states of Wisconsin and Minnesota are expected to expire Thursday night.