Lithium battery fires on U.S. flights now occur nearly twice a week, according to new FAA data. Aitrend

As millions prepare to fly for vacation, the Federal Aviation Administration is warning travelers about a hidden danger in their luggage: lithium ion batteries. Found in everyday devices like laptops, tablets and even electric toothbrushes, these batteries can catch fire if left overheat or are damaged.

Last July, panic broke out on an American Airlines flight from San Francisco to Miami after a laptop battery caught fire in carry-on luggage.

“It was absolute chaos. It really was like every man for himself. And it was terrifying,” said Shilpa Patel, a passenger on the flight. “I don’t know if we’re going to explode. All I know is that I have to get out and I have to survive.

FAA data shows that lithium battery fires on U.S. flights have increased 388% since 2015, now occurring nearly twice a week.

“Any fire at 30,000 feet is unacceptable,” said David Wroth of UL Standards & Engagement, a safety research organization.

A UL survey of more than 800 flight attendants found that 87% are concerned about lithium battery risks on planes, and more than a third say airlines should do more to keep passengers safe. Although the FAA requires airlines to include general safety information in pre-flight announcements, these warnings often do not address the specific risk of battery fires.

“It’s a balance that we probably need to get better at working with the airlines,” said Ben Supko, who oversees hazardous materials safety for the FAA. “Passengers do not fully understand the severity of the risk.”

Supko said passengers should monitor devices during a flight and immediately notify the crew if a device becomes hot, discolors or bulges. Passengers are also warned not to pack their bags lithium batteries in checked baggage, because fires in the hold are more difficult to put out.

“When you don’t know what’s going to happen, you act erratically,” Patel said. “It doesn’t cost us anything to just say, ‘Hey, the reason we’re taking this so seriously is because this could be really dangerous.’ It could catch fire.

The UL survey also found that one in four passengers admit to carrying lithium batteries in their checked baggage. This is a dangerous practice for one reason in particular: it would be even more difficult to put out a fire in the hold of an airplane.

CBS News has contacted American Airlines about the incident at the San Francisco airport and potential updates to its safety announcements. The airline did not directly address the issue but said its flight attendants receive extensive and ongoing training to handle on-board emergencies.

Ash-har Quraishi

Ash-har Quraishi is a consumer correspondent based in Chicago. He is an Emmy Award-winning journalist with more than 25 years of experience in local, national, international and investigative reporting. Her work has been featured on CNN, Al Jazeera, The PBS NewsHour, A&E, “The Oprah Winfrey Show” and in The New York Times.