Trump threatens new tariffs on Canada over wildfire smoke blanketing US cities

US President Donald Trump has threatened to impose new tariffs on Canada after hundreds of wildfires left much of the northern United States under a blanket of smoke, accusing Ottawa of "willful negligence," according to the BBC (https://www.bbc.com/news/articles/cwyq93j34lgo).

In a post on Truth Social, Trump said the United States was being "unnecessarily invaded by filthy, polluted, and unhealthy air" and said he would call Canadian Prime Minister Mark Carney to demand an explanation over his country's forest management, the BBC reports (https://www.bbc.com/news/articles/cwyq93j34lgo).

More than 190 of the blazes are burning in Ontario, some out of control. "Hazardous" air-quality alerts have been issued across the region, and on Friday Detroit recorded the world's worst air quality, followed by Chicago, Washington DC and New York, per Swiss air-quality tracker IQAir cited by the BBC (https://www.bbc.com/news/articles/cwyq93j34lgo).

Carney noted that tackling climate change is the responsibility of both nations. His emergency-management minister said the two countries remain in constant contact and pointed to a reciprocal firefighting agreement dating to 1982 and another assistance pact from the 2025 G7 summit, according to the BBC (https://www.bbc.com/news/articles/cwyq93j34lgo).

Four US lawmakers warned that their "patience has run out" and threatened direct American involvement in cross-border firefighting if Canada fails to act. But experts consulted by BBC Verify said weather ignores international borders and that better forest management cannot prevent fires across an ecosystem of this scale, the BBC reports (https://www.bbc.com/news/articles/cwyq93j34lgo).

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