A Southwest Airlines plane at Seattle-Tacoma International Airport.

Southwest Airlines passengers who use lithium-powered mobility devices will soon have to remove the batteries and carry them into the cabin before their wheelchair is checked.

The new policy will take effect on Sept. 25, and the airline said it's part of an ongoing effort to reduce the danger of fire onboard.

In a message to employees circulated Friday, Sept. 12, Dave Hunt, Southwest's vice president for safety and security, said the updated policy brings the airline in line with international safety standards.

"Lithium batteries have become one of the most common sources of smoke and fire incidents on aircraft. While these events are rare, quick access and visibility are critical to keeping everyone onboard safe. By taking proactive steps now, Southwest will be among the first U.S. carriers to adopt these higher standards," the message said.

Wheelchair batteries will not count against a passenger's carry-on baggage allowance under the new policy.

The policy also restricts the size of lithium batteries eligible for transportation on Southwest flights, to 300 watt-hours or less.

"To ease the transition, customers with batteries larger than 300 watt-hours will have a grace period through Jan. 11, 2026, while all batteries under the 300 watt-hour limit must follow the new process," a statement from the airline said. "After Jan. 11, devices with batteries above the limit will no longer be accepted for transport."

American Airlines, Delta Air Lines and United Airlines also have some restrictions for the transportation of mobility device power supplies, though each airline's rules are slightly different.

Southwest previously announced that lithium power banks need to be visible in the cabin when they're being used to recharge devices onboard, and the Federal Aviation Administration warned airlines last week that they need to evaluate their electronics fire safety procedures and messaging.

Zach Wichter is a travel reporter and writes the Cruising Altitude column for USA TODAY. He is based in New York and you can reach him at zwichter@usatoday.com.

This article originally appeared on USA TODAY: Southwest Airlines announces new restrictions on wheelchair users. Here's what to know

Reporting by Zach Wichter, USA TODAY / USA TODAY

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