Canada already is working on challenges to the U.S. tariffs under NAFTA and the WTO.

Senate measure sweetens earlier proposed deduction for pass-through entities.

Agency also says it will propose new rule in 2018 to "reconsider, revise or remove" some provisions.

If confirmed, nominee would face such construction issues as crane-operator and silica rules.

U.S. lumber companies praise Commerce Dept. action, but Canada vows a strong defense.

U.S. lumber producers praise Commerce Dept. action but Canada blasts it and threatens litigation.

The process of drafting a new proposal, taking public comments and issuing a final version is expected to be lengthy.

NAHB is concerned that lumber import restrictions could cut supply and boost prices significantly.