White House says 25% steel tariffs would stack on others as premiers in D.C. Tuesday’s news from a White House official that these two classes of tariff would stack on top of each other would mean a total 50 per cent tariff on Canadian steel and aluminum, if those planned measures proceed.

Speaking on background to CBC News, a White House official confirmed that the 25 per cent U.S. tariffs on most Canadian goods would be in addition to the 25 per cent steel and aluminum tariffs that President Donald Trump ordered Monday — meaning Canada could face 50 per cent tariffs on the metals in March.