New York CNN  — 

The Colonial Pipeline is up and running after a six-day shutdown, but some gas stations in Washington, DC and parts of the Southeast are still struggling with shortages.

In the nation’s capital, about 81% of filling stations still don’t have gasoline, according to GasBuddy, a platform that tracks fuel demand, prices and outages. The platform also indicated that 58% of North Carolina gas stations are out of gas and 48% of South Carolina stations have run dry.

The fuel pipeline, which is the largest in the US, is back in action after a cyberattack involving ransomware forced it to shut down May 7. The Colonial Pipeline spans more than 5,500 miles and transports about 45% of all the fuel consumed on the East Coast. It transports 2.5 million barrels per day of gasoline, diesel, jet fuel and home heating oil.

On Thursday, operators of the pipeline said they had made “substantial progress” in restarting the system, adding that fuel has begun flowing to most of the markets it serves.

Energy Secretary Jennifer Granholm said the successful restart of the 5,500-mile pipeline “should mean things will return to normal by the end of the weekend,” but clearly, gas stations are still struggling with supply.

The pipeline flows at just 5 miles per hour, meaning it could take days or even weeks for gasoline, diesel and jet fuel to flow through to most places and replenish nearly empty storage facilities, analysts at energy company S&P Global Platts said.

– CNN’s Matt Egan contributed to this report.