'Colonial Pipeline is taking steps to understand and resolve this issue. The company said it shut down its operations after learning of a cyberattack on Friday using ransomware. It also serves some of the country's largest airports, including Atlanta's Hartsfield Jackson Airport, the world's busiest by passenger traffic. Colonial transports 2.5 million barrels per day of gasoline, and other fuels through 5,500 miles (8,850 km) of pipelines linking refiners on the Gulf Coast to the eastern and southern United States.