Flight Risk: Portable Chargers Fuel Surge in Onboard Battery Incidents

WASHINGTON, D.C. – August 13, 2026 – The convenience of modern travel, powered by a host of personal electronic devices, is introducing a growing and costly risk at 35,000 feet. A new report from safety science organization UL Standards & Engagement (ULSE) reveals a troubling upward trend in lithium-ion battery incidents on passenger flights, with portable chargers—the ubiquitous power banks tucked into countless carry-ons—now identified as the leading source of in-flight fires and thermal runaway events.

The third annual ‘Lithium-ion Battery Incidents in Aviation: 2025 Data Review’ paints a stark picture: incidents are not only increasing in frequency but are also creating significant safety challenges and financial burdens for the aviation industry. The findings highlight a critical disconnect between the proliferation of these devices and passenger awareness of the dangers they can pose.

"Every incident is a safety risk, and the trend line is moving in the wrong direction," said Jeff Marootian, president and CEO of UL Standards & Engagement, in a statement accompanying the release. His message underscores a core theme of the report: while technology powers our lives, managing its risks is a shared responsibility. "Passengers do not need to be safety experts to reduce the risk. Keeping rechargeable devices within reach can help us all fly in safer skies."

A Problem in Our Pockets and Bags

The data, compiled from over 40 airlines participating in ULSE’s Thermal Runaway Incident Program (TRIP), shows a 15% increase in battery-related events from 2024 to 2025. This continues a steady climb that has safety experts and airline executives on high alert. The average number of weekly incidents has now reached 2.36, up from 2.05 the previous year, translating to more than two potential emergencies every week across the participating carriers alone.

Most alarming is the specific culprit driving this surge. Incidents involving portable chargers, or power banks, jumped a staggering 42% over the last year. This has propelled them past e-cigarettes, the primary source of incidents in 2024, which themselves saw a 26% increase. Cellular phones round out the top three most common devices linked to thermal runaway events.

The danger lies in a phenomenon called thermal runaway, a rapid, uncontrollable chain reaction where a battery cell's temperature rises, causing it to vent flammable gas, smoke, and often fire. These fires are notoriously difficult to extinguish with traditional onboard equipment like halon extinguishers and are prone to reignition. The risk is magnified when a device is packed in checked luggage in the cargo hold, where an event can go undetected and is nearly impossible for the crew to address.

“Year after year, we continue to see battery incidents rise, underscoring the need for action,” said David Wroth, who leads ULSE’s Thermal Runaway Incident Program. “There is no silver-bullet solution to this growing safety challenge, which is why we’re working across the industry to better understand the risks and identify solutions that can help prevent a serious or catastrophic event.”

The Multi-Million Dollar Disruption

Beyond the immediate safety threat, these incidents represent a significant and escalating financial drain on the aviation industry. ULSE’s report, which includes economic data for the first time, conservatively estimates that battery incidents have cost the commercial aviation sector approximately $7.3 million between 2021 and 2024. This breaks down to an average of $1.8 million per year, or about $96,000 per incident.

These figures account for a range of direct and indirect costs, including damage to the aircraft interior, the cost of flight diversions, operational disruptions, and passenger re-accommodation. A single overheating device can force a plane to return to the gate, divert to an alternate airport, or require extensive post-flight inspection and repair, creating a ripple effect of delays and cancellations throughout an airline's network. These costs do not even factor in the potential for increased insurance premiums or the reputational damage that can follow a widely publicized safety event.

This financial pressure comes as airlines are already navigating a complex post-pandemic recovery, making the mitigation of such preventable incidents a key strategic priority. The costs reinforce the business case for investing in enhanced crew training and specialized safety equipment.

Industry in Response: Policies, Preparedness, and a Patchwork of Rules

The aviation industry is not standing still. In response to the growing threat, major carriers including United, Delta, American, and Southwest have been rolling out new policies and reinforcing existing guidelines around the carriage and use of lithium-ion batteries. The Federal Aviation Administration (FAA) has been vocal, issuing a safety alert to airlines after its own data showed a record 96 battery incidents in 2025, with 82 occurring on passenger flights.

The core of these policies is the FAA mandate that all spare lithium-ion batteries and power banks must be carried in the cabin, not in checked baggage. The logic is simple: if a device begins to overheat in the cabin, the crew has a chance to intervene. However, as the ULSE report highlights, passenger awareness and compliance remain the weakest links in this safety chain.

In response, some airlines are going beyond mere policy and investing in hardware. A growing number are equipping their fleets with specialized fire-containment bags, some certified to ULSE’s own UL 5800 standard, designed to safely hold a device experiencing thermal runaway and contain the fire, smoke, and heat until the flight can land safely. This strategic shift from a reactive to a prepared posture marks a significant evolution in how the industry is managing the risk.

The Global Awareness Gap

Perhaps one of the most intriguing findings in the 2025 report is the significant global disparity in passenger attitudes toward battery safety. For the first time, the ULSE survey included global data, revealing that travelers in the Asia-Pacific region (83%) and Latin America (79%) report much higher levels of concern about battery incidents than their counterparts in Europe (74%) and North America (67%).

This awareness gap has profound implications for global airlines and safety bodies. Passengers in regions with higher concern are also more supportive of additional safety measures, suggesting a greater willingness to comply with stricter rules and listen to educational campaigns. The lower levels of concern in North America, a massive travel market, are particularly notable given the high rate of device ownership and use.

Qualitative research from ULSE found that while 97% of cabin crew members are aware of the risks, only 65% of passengers surveyed reported similar awareness. This chasm explains why, despite airline rules and FAA mandates, dangerous practices like packing power banks in checked luggage persist.

As Jeff Marootian concluded, “Airlines are taking the risk seriously, strengthening policies and training crew to respond when incidents occur. But they cannot solve this problem alone. Passengers need to understand the risks and know what to do before the rechargeable device becomes a safety threat.” The path to safer skies, it seems, requires not just new rules and technology, but a fundamental shift in the mindset of the modern connected traveler.