As more than 100 million Americans are under air quality alerts, Trump says Ottawa is being “wilfully negligent” about wildfire smoke that’s blanketing 18 US states, and threatens to impose additional tariffs on pollution costs.

US President Donald Trump threatened to increase existing tariffs and blamed his northern neighbor for the cost of wildfire smoke that has filled much of the United States in a dangerous haze on Friday, calling the air on the border “filthy, polluted, and unhealthy” and accusing Canada of “wilful negligence.”
The warning was made on the platform Trump has used for his most pointed political messages, and was received by over 100 million Americans in 18 states and the District of Columbia already under active air quality alerts.

What Trump said

“We are holding Canada responsible for the fact that they are not properly maintaining their Forests, and Brush therein, and the United States is being unnecessarily invaded by filthy, polluted, and unhealthy air, the quality of which is dangerous, and totally unacceptable!” Trump wrote. He described the situation as “totally unacceptable” and said the billions of dollars in costs inflicted on the US as a result of the air pollution “must of necessity be added to the tariffs Canada is currently paying.
Trump also stated he would reach out to Prime Minister Mark Carney in the day to see “what they are going to do about it,” using the word “it” to refer to the issue as not only an environmental concern but a trade and sovereignty issue as well.
The scale of the smoke crisis is massive. The immediate cause is true and serious. Wildfires have been getting worse in Canada in recent weeks, especially in Northwestern Ontario, where thousands of people have been evacuated. The smoke from the fires has spread southward over the border, and the “very unhealthy” and “hazardous” air quality is in a band from northeast Minnesota to southeast Virginia.
The haze has been seen from the ground in major cities in the United States. Images of a Manhattan skyline in a thick layer of smoke, with a dark orange haze obscuring the view, were shared widely on social media on Friday morning. The poor air quality has also led to concerns about the FIFA World Cup final, which is set to take place on Sunday in the northeast of New Jersey, where Trump is expected to attend. On Friday, he went to New York City for a FIFA reception at Trump Tower.

Carney’s Response

In an X post earlier this week, Carney admitted that the wildfire situation has “escalated significantly” in recent weeks. He didn’t speak specifically about Trump’s tariff threat, but on Thursday he did provide a pointed response to any suggestion that Canada’s environmental management is being criticized. We have our own responsibility, he told reporters in French, “at the moment we are stressing investment in clean energy, but in the US there are modes of production that are fighting clean energy.
The answer is indicative of a pattern that has been a hallmark of Carney’s approach to Trump. The Canadian prime minister has consistently declined to be baited into public conflicts with Trump and has made it clear, in diplomatic terms, that Canada does not accept the premise of the criticism being aimed at it since he took office.

A series of escalating threats of tariffs

The threat on Friday comes on the heels of a series of tariff provocations against Canada since Trump took office. In that post, earlier this year, Trump threatened to impose a 100% tariff on Canadian goods if Ottawa went ahead with its trade deal with China, using the term “Governor” to intentionally insult Carney, suggesting Canada is a US state, not a sovereign nation. That nickname was previously given to Carney by Trump in his attacks on former Prime Minister Justin Trudeau.
Canada was the second-largest exporter to the US in 2025, with more than $300 billion in goods, or more than 11% of all US imports. But the two countries are also in the midst of renegotiating the USMCA, the North American free trade agreement, which provides both sides with more leverage and more points of friction in the relationship.

Scientists push back on the framing

Climate change, caused by human activities, has been shown to make wildfires in Canada and the western US more frequent, severe, and widespread. While forest management practices do influence fire behaviour, the main reason for the increasing wildfire crisis in Canada – especially in the boreal forest areas of Northwestern Ontario – is due to climate warming and drying, not maintenance failures as Trump claims.
The Canadian government has admitted its wildfire crisis is worsening, in part due to hotter and drier climate. At the time of writing, there was no word from Ottawa on the specific threat to tariffs, and it was not clear how or whether Trump planned to specify and formalize the tariff addition he is proposing.