NDP - Tariff on Mexican oil would slap U.S. refiners adding to costs May, 31 2019 12:57 PM Tortoise Energy Independence Fund Inc. It's been a tough day for U.S. Gulf of Mexico oil refiners, thumped by Pres. Trump's threats to slap a tariff on all goods coming from Mexico and the EPA's widely expected move to allow year-round sale of E15 gasoline.More news on: Valero Energy Corporation, Phillips 66, Exxon Mobil Corporation, Energy stocks news, Stocks on the move, News on ETFs, Read more ...