U.S. and industry officials have known for years about such problems surrounding the nation’s energy infrastructure. A cybersecurity unit of Homeland Security said in 2016 it had worked to identify and mitigate 186 vulnerabilities throughout the energy sector, the most of any critical-infrastructure industry that year. In 2018, federal officials warned that hackers working for Russia had infiltrated the control rooms of U.S. electric utilities. The energy industry is a big target. The U.S. has roughly 2.5 million miles of pipelines. Across that vast network are hundreds of thousands of devices—sensors that take myriad readings, valves that help control flow and pressure within a pipeline and leak detection systems—and all are vulnerable to attack, security experts said. Refineries have even more valves and sensors than big pipelines, and there are about 135 of those across the country. That doesn’t include electric utilities and all the components of the sprawling power grid. Colonial ferries 100 million gallons a day of gasoline, diesel and other refined petroleum products from the country’s chief refining corridor along the Gulf Coast to Linden, N.J. It transports roughly 45% of the fuel consumed on the East Coast, according to the company’s website.