(Bloomberg) -- Fuel suppliers are growing increasingly nervous about the possibility of gasoline and diesel shortages across the eastern U.S. almost two days after a cyberattack knocked out a massive pipeline.Colonial Pipeline said Sunday that it was still developing a plan for restarting the nation’s largest fuel pipeline -- a critical source of supply for the New York region -- and would only bring it back when “safe to do so, and in full compliance with the approval of all federal regulations.” Gasoline futures surged by as much as 4.2% in early electronic trading on Sunday.The attack comes just as the nation’s energy industry is preparing to meet stronger fuel demand from summer travel. Americans are once again commuting to the office, planning major travel for the first time and booking flights. A prolonged disruption along the pipeline system threatens to send average U.S. gasoline prices above $3 a gallon for the first time since October 2014, further stoking fears of inflation as commodity prices rally worldwide.With little to no clarity over when the system will return, traders are seeking vessels to deliver gasoline that would have otherwise been shipped on the Colonial system, according to market participants who asked not to be identified because the information isn’t public. Some tankers are being secured to temporarily store gasoline in the U.S. Gulf in the event of a prolonged shutdown, they said.Colonial halted all operations on its system late Friday after suffering a ransomware attack that affected some of its IT systems.Colonial is just the latest example of critical infrastructure being targeted by ransomware. Hackers are increasingly attempting to infiltrate essential services such as electric grids and hospitals. The escalating threats prompted the White House to respond last month with a plan to increase security at utilities and their suppliers. Pipelines are a specific concern because of the central role they play in the U.S. economy.“It’s an all-hands-on-deck effort right now,” U.S. Commerce Secretary Gina Raimondo said of federal government actions as the shutdown drags on. “We are working closely with the company, state and local officials to make sure that they get back up to normal operations as quickly as possible and there aren’t disruptions in supply.”Colonial is a major source of gasoline, diesel and jet fuel to the East Coast from the nation’s refining belt along the U.S. Gulf Coast. It has the capacity to send about 2.5 million barrels a day on its system from Houston as far as North Carolina, and another 900,000 barrels a day to New York.The attack appeared to use a ransomware group called DarkSide, according to Allan Liska, senior threat analyst at cybersecurity firm Recorded Future. The cybersecurity firm FireEye Inc. said its Mandiant incident response division was assisting with the investigation.Extortion FeeRansomware cases involve hackers seeding networks with malicious software that encrypts the data and leaves the machines locked until the victims pay the extortion fee. This would be the biggest attack of its kind on a U.S. fuel pipeline.The national gasoline average stood at $2.96 a gallon Friday, according to auto club AAA. With gasoline inventories ample, the pump price wasn’t expected to tick much higher until Memorial Day at the end of May, which is traditionally viewed as the start of the U.S. summer driving season. If the pipeline doesn’t restart soon it will accelerate the move higher.“I think we’re at strong odds for it by Memorial Day given current trends,” said Patrick De Haan, head of petroleum analysis at Gas Buddy.A key concern at present is meeting product demand in the U.S. Southeast, which is especially dependent on the Colonial system, people familiar with the situation said. Drivers in landlocked and car-dependent Atlanta may be the first to feel the pinch at the pump.“Atlanta will be one of the earlier sore spots, along with eastern Tennessee, and perhaps the Carolinas,” De Haan said.The Northeast can secure gasoline shipments from Europe but it will come at an increasing cost the longer the pipeline stays shut.“The longer it lasts, the more bullish it will be for refined products on the East Coast,” said Warren Patterson, head of commodities strategy at ING Groep NV. “This will likely also drag European product prices higher, as we see more waterborne cargoes needing to go into the U.S. East Coast to meet the shortfall.”Airports on the East Coast, which continue to have some of the steepest drops in air traffic due to the pandemic, have been operating smoothly Sunday, according to the flight-tracking website FlightAware.com.In the meantime, fuel producers including Marathon Petroleum Corp. are weighing alternatives for how to ship their products to the Northeast.One potential route is the Kinder Morgan-operated Plantation Pipeline, even though it only extends as far north Washington D.C. and has a capacity of 720,000 barrels a day, far short of Colonial’s. Kinder said Sunday it’s working with customers to accommodate additional barrels during Colonial’s outage, and that Plantation is deferring where possible any non-essential maintenance that might otherwise reduce flow rates.While all of the major segments of Colonial’s system remain offline, some smaller so-called laterals connecting specific fuel terminals to delivery points are in service, the company said. That laterals gave some traders hope that the full network may be back online within a week. “Hopefully it is a sign that they have made progress either negotiating with those responsible for the attack or have found ways to operate around it, said Debnil Chowdhury, head of Americas refining at IHS Markit. “However to avoid product shortages, all efforts should be made to avoid a 5+ day outage of the main lines.”Inventories offer minimal cover, ClearView Energy Partners said in a research note. Tankers leaving Rotterdam could take up to 14 days to make the trip to the New York Harbor. The Midwest could theoretically send some of its supplies to the East Coast via rail and barge, but the region’s inventories are tighter than in previous years, ClearView said.“The Colonial outage comes at a critical juncture for the recovering U.S. economy: the start of the summer driving season,” ClearView said. “We therefore think lawmakers could begin a ‘blame game’ immediately, and a sustained disruption that leads to a significant pump price spike could increase prospects of domestic policy interventions.”For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2021 Bloomberg L.P.