U.S. refiners warned the Trump administration that tariffs on imports from Mexico could deliver a punishing blow to refiners and raise the cost of gasoline just as the U.S. driving season kicks into high gear, according to sources familiar with the discussions. Trump surprised Mexico last week with a threat to impose 5% tariffs on all its exports to the United States unless the Mexican government took measures to stem the flow of illegal immigrants into the United States. The United States imports over 650,000 barrels of crude per day from Mexico, about 10% of total crude imports, according to U.S. government data. Refiners are also worried that Mexico could retaliate with tariffs on its imports of U.S. fuel, a major source of revenue for […]