The Canadian government has initiated an anti-dumping review of gypsum wallboard exports from the U.S. While this appears to be a stand-alone case it comes during a lull in NAFTA negotiations and has parallels in the controversial softwood lumber case, also in the building materials sector. The case will have a significant impact on U.S. manufacturers as Canada accounts for 90% of exports while shipments to Canada have already fallen 13% annually over the past three years.