More info on US 25% steel tariffs would stack on other levies on Canada

I posted earlier:

• White House says 25% steel tariffs would stack on top of other levies

Reuters adding a little more now:

• Trump's planned 25% tariffs on all steel and aluminum imports would be added onto other levies on Canadian goods, resulting in a total 50% tariff, a White House official said on Tuesday.
• Canada has not been told about the stacking of the tariffs, a government source told Reuters, adding that it "sounds plausible."

***

Huh. 50% sounds insane.