The fight against allegedly under-priced copper pipe and tube imports from China and Mexico has advanced to the next level, but several hurdles lie ahead.

The U.S. International Trade Commission (ITC) voted unanimously to continue its dumping investigation of imports of seamless refined copper pipe and tube, validating allegations that such imports have threatened to cause material injury to North American producers.

"(The) unanimous ITC vote should send a clear signal to copper tube producers in China and Mexico that unfair trade practices will be met with anti-dumping duties at the U.S. border," Jack Levy, counsel for the petitioners and partner at Washington law firm DLA Piper US LLP, said in a statement.

Friday's affirmative vote by the ITC was a crucial step forward for the domestic copper tube producers—Cerro Flow Products Inc., KobeWieland Copper Products LLC and two Mueller Industries Inc. divisions—that...