Data: U. S. Census Bureau, U. S. Department of Agriculture, U. S Data: U.S. Census Bureau, U.S. Department of Agriculture, U.S. Energy Information Administration, Data Transmission Network, Center for Automotive Research, BMW Group, Daimler Tesla’s Fremont factory is the sixth-biggest car plant exporting to China. Tesla has announced a deal with the Shanghai government to build an assembly plant there. The Texas port districts of Houston-Galveston and nearby Port Arthur handled 82 percent of crude exports to China in 2017 (worth $3.6 billion), which will be targeted if the U.S. government follows through on a threatened second round of anti-Chinese tariffs. In 2016 Iowa exported more than $3 billion in soybeans and $2 billion in pork, almost three times what ­runner-up Minnesota shipped. These commodities are the single biggest tariff targets for China and Mexico, respectively. BMW’s sprawling Spartanburg car plant, which employs more than 10,000 people and sits atop a network of 235 American suppliers, is responsible for the most U.S.-produced cars exported to China.