What we know about the fire that brought London's Heathrow Airport to a standstill

LONDON (AP) — Heathrow Airport was up and running Saturday and airlines worked to clear the backlog after a fire at a nearby electricity substation knocked out power to Europe's busiest airport, disrupting travel plans for hundreds of thousands of people around the world.

The airport said it had made space for extra flights, but it is expected to take days to get stranded passengers to their destinations and displaced aircraft into the proper locations.

Here's a look at what happened and its impact on air travel.

A fire at an electrical substation in west London, about 2 miles (3.2 kilometers) from the airport, cut power to Heathrow Airport late on Thursday.

Residents reported an explosion and a fireball just before midnight. The London Fire Brigade said a transformer holding 25,000 liters (5,000 gallons) of cooling oil caught fire. It said 10 fire engines and 70 firefighters brought the blaze under control after seven hours, but isolated hotspots were still alight 24 hours after the fire started.

National Grid, which maintains energy infrastructure in Britain, said the blaze damaged equipment at the substation and cut power to 67,000 properties, including Heathrow. It said power was restored to all of them by Saturday morning.

The “significant power outage” initially forced Heathrow officials to announce that the airport would be closed until 11:59 p.m. on Friday, but some flights began to resume on Friday evening.

Officials said there was no suggestion of foul play, but the cause is still under investigation. The fire brigade said its investigation would focus on the electrical distribution equipment at the substation.

Even so, London's Metropolitan Police Service said counterterrorism detectives were leading the investigation because of the fire's impact on critical national infrastructure.

Energy Secretary Ed Miliband said it was "an unprecedented event.”

“Obviously, with any incident like this we will want to understand why it happened and what if any lessons it has for our infrastructure,” he told Sky News.

The closure disrupted the travel plans of around 200,000 people who were expected to travel through Heathrow on Friday. Heathrow advised passengers not to travel to the airport and to contact their airlines to rebook flights.

With all takeoffs and landings canceled, the first impact was on dozens of long-haul flights from North America and Asia that were in the air when the airport was shut down. Some were forced to turn around, while others were diverted to airports around the United Kingdom and Europe.

Heathrow-bound aircraft landed at Schiphol Airport in Amsterdam; Shannon Airport in western Ireland; Glasgow, Scotland; Manchester, England; Charles de Gaulle in Paris; Lyon, France; and Frankfurt, Germany, among others.

About 4,000 tons of cargo were also stranded by the closure, according to Anita Mendiratta, an aviation and leadership consultant.

The disruptions are expected to last for days as airlines move stranded aircraft and flight crews back into position and work to accommodate passengers whose flights were canceled. Mendiratta estimated that it would take two to four days to clear all the backlogs.

“This is an extreme situation where the entire aviation ecosystem is impacted,” she said.

“There will be two things that will be happening as a priority No. 1. First is airport operations and understanding, from an electrical system point of view, what has been impacted, if anything,” she said. “Did anything short out, for instance? What needs to be reactivated? And then how do you literally turn the airport back on again?"

Heathrow was Europe’s busiest airport last year, with 83.6 million passengers traveling through it. Its closure will have far-reaching impacts because it's a major hub for connecting flights to cities throughout the U.K. and around the world, as well as for travel to London.

Yes. Five other air hubs in southeastern England identify themselves as London airports, but they are much smaller than Heathrow. London Gatwick, Britain’s second-biggest airport, handled 43.2 million passengers last year. It's located in the town of Crawley, 28 miles (45 kilometers) south of London.

The fire raises concerns about the U.K.’s ability to withstand attacks or natural disasters that damage critical infrastructure such as communications and power networks, analysts said.

The incident is particularly worrisome given recent comments by Britain’s security services that Russia is conducting a reckless campaign of sabotage across Europe, said Alan Mendoza, the executive director of the Henry Jackson Society, a London-based security think tank.

“The U.K.’s critical national infrastructure is not sufficiently hardened for anywhere near the level it would need to be at to give us confidence this won’t happen again,” he said. “I mean, if one fire can shut down Heathrow’s primary systems ... it tells you something’s badly wrong with our system of management of such disasters.”

Robin Potter, an expert on resilience at London-based think tank Chatham House, said that successive governments have been slow to respond to repeated recommendations from the National Infrastructure Commission to strengthen the ability of Britain’s power, communications, transport and water networks to withstand major shocks.

“We still have yet to see a kind of clear response from the government to those recommendations,” he said. “And we hope that maybe in the government’s upcoming resilience review, which we expect will be published at some point this year, it might seek to address some of those questions.”

Heathrow defended its response. Its CEO Thomas Woldbye said “the same would happen in other airports” faced with a similar fire.

A plane takes off as Heathrow Airport slowly resumes flights after a fire cut power to Europe's busiest airport in London, Saturday, March 22, 2025.(AP Photo/Kirsty Wigglesworth)

Passengers on a bus look at a parked plane as Britain's Heathrow Airport has closed for the full day Friday after an electrical substation fire knocked out its power, disrupting flights for hundreds of thousands of passengers at one of Europe's biggest travel hubs in London, Friday, March 21, 2025.(AP Photo/Kin Cheung)

Planes are parked at the Terminal as Britain's Heathrow Airport has closed for the full day Friday after an electrical substation fire knocked out its power, disrupting flights for hundreds of thousands of passengers at one of Europe's biggest travel hubs in London, Friday, March 21, 2025.(AP Photo/Kin Cheung)

This image taken from video shows parked planes at Heathrow airport, as a fire at the North Hyde electrical substation on Thursday night has led to a closure of Heathrow Airport in London, Friday, March 21, 2025. (Sky News via AP)

Omar Sheikh from Pakistan checks his phone whilst standing beside his lugage at Terminal 4 as Britain's Heathrow Airport has closed for the full day Friday after an electrical substation fire knocked out its power, disrupting flights for hundreds of thousands of passengers at one of Europe's biggest travel hubs in London, Friday, March 21, 2025.(AP Photo/Kin Cheung)

No travellers are seen inside Terminal 4 as Britain's Heathrow Airport has closed for the full day Friday after an electrical substation fire knocked out its power, disrupting flights for hundreds of thousands of passengers at one of Europe's biggest travel hubs in London, Friday, March 21, 2025.(AP Photo/Kin Cheung)

Smoke still rises as firefighters inspect the site of the fire at the North Hyde electrical substation, which caught fire Thursday night and lead to the closure of Heathrow Airport in London, Friday, March 21, 2025.(AP Photo/Kirsty Wigglesworth)

This image taken from video shows firefighters working to secure the area of a fire at the North Hyde electrical substation, which caught fire Thursday night and lead to a closure of Heathrow Airport in London, Friday, March 21, 2025. (Sky News via AP)

WASHINGTON (AP) — Becky Pepper-Jackson finished third in the discus throw in West Virginia last year though she was in just her first year of high school. Now a 15-year-old sophomore, Pepper-Jackson is aware that her upcoming season could be her last.

West Virginia has banned transgender girls like Pepper-Jackson from competing in girls and women's sports, and is among the more than two dozen states with similar laws. Though the West Virginia law has been blocked by lower courts, the outcome could be different at the conservative-dominated Supreme Court, which has allowed multiple restrictions on transgender people to be enforced in the past year.

The justices are hearing arguments Tuesday in two cases over whether the sports bans violate the Constitution or the landmark federal law known as Title IX that prohibits sex discrimination in education. The second case comes from Idaho, where college student Lindsay Hecox challenged that state's law.

Decisions are expected by early summer.

President Donald Trump's Republican administration has targeted transgender Americans from the first day of his second term, including ousting transgender people from the military and declaring that gender is immutable and determined at birth.

Pepper-Jackson has become the face of the nationwide battle over the participation of transgender girls in athletics that has played out at both the state and federal levels as Republicans have leveraged the issue as a fight for athletic fairness for women and girls.

“I think it’s something that needs to be done,” Pepper-Jackson said in an interview with The Associated Press that was conducted over Zoom. “It’s something I’m here to do because ... this is important to me. I know it’s important to other people. So, like, I’m here for it.”

She sat alongside her mother, Heather Jackson, on a sofa in their home just outside Bridgeport, a rural West Virginia community about 40 miles southwest of Morgantown, to talk about a legal fight that began when she was a middle schooler who finished near the back of the pack in cross-country races.

Pepper-Jackson has grown into a competitive discus and shot put thrower. In addition to the bronze medal in the discus, she finished eighth among shot putters.

She attributes her success to hard work, practicing at school and in her backyard, and lifting weights. Pepper-Jackson has been taking puberty-blocking medication and has publicly identified as a girl since she was in the third grade, though the Supreme Court's decision in June upholding state bans on gender-affirming medical treatment for minors has forced her to go out of state for care.

Her very improvement as an athlete has been cited as a reason she should not be allowed to compete against girls.

“There are immutable physical and biological characteristic differences between men and women that make men bigger, stronger, and faster than women. And if we allow biological males to play sports against biological females, those differences will erode the ability and the places for women in these sports which we have fought so hard for over the last 50 years,” West Virginia's attorney general, JB McCuskey, said in an AP interview. McCuskey said he is not aware of any other transgender athlete in the state who has competed or is trying to compete in girls or women’s sports.

Despite the small numbers of transgender athletes, the issue has taken on outsize importance. The NCAA and the U.S. Olympic and Paralympic Committees banned transgender women from women's sports after Trump signed an executive order aimed at barring their participation.

The public generally is supportive of the limits. An Associated Press-NORC Center for Public Affairs Research poll conducted in October 2025 found that about 6 in 10 U.S. adults “strongly” or “somewhat” favored requiring transgender children and teenagers to only compete on sports teams that match the sex they were assigned at birth, not the gender they identify with, while about 2 in 10 were “strongly” or “somewhat” opposed and about one-quarter did not have an opinion.

About 2.1 million adults, or 0.8%, and 724,000 people age 13 to 17, or 3.3%, identify as transgender in the U.S., according to the Williams Institute at the UCLA School of Law.

Those allied with the administration on the issue paint it in broader terms than just sports, pointing to state laws, Trump administration policies and court rulings against transgender people.

"I think there are cultural, political, legal headwinds all supporting this notion that it’s just a lie that a man can be a woman," said John Bursch, a lawyer with the conservative Christian law firm Alliance Defending Freedom that has led the legal campaign against transgender people. “And if we want a society that respects women and girls, then we need to come to terms with that truth. And the sooner that we do that, the better it will be for women everywhere, whether that be in high school sports teams, high school locker rooms and showers, abused women’s shelters, women’s prisons.”

But Heather Jackson offered different terms to describe the effort to keep her daughter off West Virginia's playing fields.

“Hatred. It’s nothing but hatred,” she said. "This community is the community du jour. We have a long history of isolating marginalized parts of the community.”

Pepper-Jackson has seen some of the uglier side of the debate on display, including when a competitor wore a T-shirt at the championship meet that said, “Men Don't Belong in Women's Sports.”

“I wish these people would educate themselves. Just so they would know that I’m just there to have a good time. That’s it. But it just, it hurts sometimes, like, it gets to me sometimes, but I try to brush it off,” she said.

One schoolmate, identified as A.C. in court papers, said Pepper-Jackson has herself used graphic language in sexually bullying her teammates.

Asked whether she said any of what is alleged, Pepper-Jackson said, “I did not. And the school ruled that there was no evidence to prove that it was true.”

The legal fight will turn on whether the Constitution's equal protection clause or the Title IX anti-discrimination law protects transgender people.

The court ruled in 2020 that workplace discrimination against transgender people is sex discrimination, but refused to extend the logic of that decision to the case over health care for transgender minors.

The court has been deluged by dueling legal briefs from Republican- and Democratic-led states, members of Congress, athletes, doctors, scientists and scholars.

The outcome also could influence separate legal efforts seeking to bar transgender athletes in states that have continued to allow them to compete.

If Pepper-Jackson is forced to stop competing, she said she will still be able to lift weights and continue playing trumpet in the school concert and jazz bands.

“It will hurt a lot, and I know it will, but that’s what I’ll have to do,” she said.

Heather Jackson, left, and Becky Pepper-Jackson pose for a photograph outside of the U.S. Supreme Court in Washington, Sunday, Jan. 11, 2026. (AP Photo/Jose Luis Magana)

Heather Jackson, left, and Becky Pepper-Jackson pose for a photograph outside of the U.S. Supreme Court in Washington, Sunday, Jan. 11, 2026. (AP Photo/Jose Luis Magana)

Becky Pepper-Jackson poses for a photograph outside of the U.S. Supreme Court in Washington, Sunday, Jan. 11, 2026. (AP Photo/Jose Luis Magana)

The Supreme Court stands is Washington, Friday, Jan. 9, 2026. (AP Photo/J. Scott Applewhite)

FILE - Protestors hold signs during a rally at the state capitol in Charleston, W.Va., on March 9, 2023. (AP Photo/Chris Jackson, file)