The U.K. government is ordering an investigation into the electrical substation fire that shut down London's Heathrow Airport for nearly a day, which led to the cancellation of more than 1,300 flights, and stalled all air traffic through the major travel hub, including air freight. 

The probe will focus on Heathrow's "energy resilience," the Associated Press reports, to determine how the March 21 fire had such wide-ranging impacts on the entire airport. 

“This is a huge embarrassment for Heathrow Airport," Labour Party leader Toby Harris said. "It’s a huge embarrassment for the country that a fire in one electricity substation can have such a devastating effect."

Heathrow will conduct its own investigation as well, which will be headed by airport board member and former transportation secretary Ruth Kelly. She's expected to look into "the robustness and execution" of Heathrow's crisis management processes, and how the airport responded to and recovered from the incident, Heathrow chairman Paul Deighton told the AP.

Although the airport was fully operational again by March 22, travel disruptions are expected to last for days as airlines and cargo operators work to rebook canceled flights. The wider air freight impacts are unclear at this point, although Heathrow accounted for £105 billion ($135 million) of the country's air freight imports in 2024, according to data from S&P Global Market Intelligence. Moody's director Vitaliano Tobruk also expects any congestion to "ripple outward" to other European cargo hubs in Germany and France. 

"Any companies that rely on supply chains which are too dependent on single transit points would now be facing difficulties," he added.