"Restoring our network to normal operations is a process that requires the diligent remediation of our systems, and this takes time," the company said in a statement.
"In response to the cybersecurity attack on our system, we proactively took certain systems offline to contain the threat, which temporarily halted all pipeline operations, and affected some of our IT systems. To restore service, we must work to ensure that each of these systems can be brought back online safely."
Colonial's restart plan, in compliance with relevant federal regulations and in close consultation with the Department of Energy, will bring service back online through a phased approach.
"This plan is based on a number of factors with safety and compliance driving our operational decisions, and the goal of substantially restoring operational service by the end of the week," Colonial noted.
The company added that it continues to evaluate product inventory in storage tanks at its facilities and others along its system and is working with shippers to move the product to terminals for local delivery.
The White House established an interagency working group to help resolve the issue and the Department of Transportation issued a temporary hours of service exemption to offer more flexibility to motor carriers and drivers transporting gasoline, diesel, jet fuel and other refined petroleum products and to help alleviate local supply disruptions.
"Our primary focus continues to be the safe and efficient restoration of service to our pipeline system, while minimizing disruption to our customers and all those who rely on Colonial Pipeline," Colonial's statement concluded. "We appreciate the patience of the traveling public and the support we have received from the Federal Government and our peers throughout the industry."
Colonial Pipeline operates a 5,500-mile system taking fuel from the refineries of the Gulf Coast to the New York metro area. The pipeline transports more than 100 million gallons a day, or roughly 45% of fuel consumed on the East Coast, according to the company's website. It delivers gasoline, diesel, jet fuel and heating oil and serves U.S. military facilities.
Colonial's update comes as the American Automobile Association reported that the national average for gas prices jumped 6 cents to $2.96, and is poised to rise even higher due to the disruption.
"This shutdown will have implications on both gasoline supply and prices, but the impact will vary regionally," AAA spokesperson Jeanette McGee said in a statement. "Areas including Mississippi, Tennessee and the East Coast from Georgia into Delaware are most likely to experience limited fuel availability and price increases, as early as this week. These states may see prices increase 3 to 7 cents this week."
An increase of 3 more cents would make the national average the most expensive since November 2014, when average gas prices were $2.99 and higher.
AAA estimates that once the Colonial Pipeline system is back up and running, there could be residual delays as it takes about 15 to 18 days for fuel to flow from Texas to New York.