Battery catches fire on United flight, causing plane to make emergency landing in San Diego

A laptop battery caught fire aboard a United Airlines flight headed for Newark this morning, sending four people to the hospital.

The plane, a Boeing 737 MAX 8, took off from San Diego but then returned to the San Diego International Airport about half an hour later after a laptop's external battery pack ignited in the cabin, according to The New York Times. Flight attendants were quick to place the burning battery into a "fire bag" to stop the fire from spreading, but four people were later treated at the hospital for smoke inhalation. Others were treated on site.

From the Times:

United Airlines said that "a customer's battery pack ignited."

"Our crew acted quickly to contain the device and medical personnel met the aircraft upon arrival at the gate," the airline said in a statement. "Several flight attendants were taken to the hospital as a precaution and two customers were evaluated on site." …

Sabrina LoPiccolo, an airport spokeswoman, said that the plane had "declared an Alert 2" after takeoff, indicating a "major difficulty with the aircraft." …

U.C. San Diego Medical Center said in a statement that four patients were treated there for smoke inhalation.

In its statement, United thanked the crew members "for their quick actions in prioritizing the safety of everyone on board." The airline said it was making arrangements to get passengers to their destinations.

Lithium-ion batteries, used in laptops, phones, toothbrushes and other electronic devices, have been known to overheat or cause fires.