July 28, 2012. Proposed U.S. tariffs on wind-energy towers from China and Vietnam were welcomed by a trade group that had complained competitors were dumping products in the American market. The Commerce Department concluded in preliminary findings that producers in the nations, which exported $301 million in towers to the U.S. in 2011, sold the utility-scale goods below production costs. The department, which set duties as high as 73 percent for Chinese products and 60 percent for goods from Vietnam, acted on a complaint by U.S. companies such as Broadwind Energy Inc. of Naperville, Illinois. Broadwind rose 13 percent in trading. The U.S. has imposed duties on numerous types of renewable- energy products from China in recent months, prompting retaliation in an escalation of trade tensions between the world's two largest economies. President Barack Obama and Republican presidential candidate Mitt Romney have pledged stronger enforcement of trade actions against China, ahead of U.S. elections in November.