A hydrogen-powered bus exploded at a charging station in Chungju, North Chungcheong Province, Monday. Courtesy of the Chungju city government

The explosion of a hydrogen bus in Chungju, a city located in the center of Korea, has raised safety concerns about the fuel type, which is often viewed as a safe and sustainable energy source for the future of transportation.

An official at the city's charging station and two other individuals were injured in an explosion on Monday, as the vehicle was starting its engine after charging, causing the rear of the vehicle to be blown off.

Investigators from relevant organizations, including the Korea Gas Safety Corporation (KGS), began to look into the case immediately, prompting the city's authorities to suspend operations of all 18 hydrogen-powered buses.

According to the KGS and industry experts, this is the first such incident in Korea since the introduction of commercial hydrogen fuel cell vehicles (HFCVs) more than 10 years ago.

"Data shows that was the first explosion involving an HFCV. Hydrogen is a safe energy source, but there is no 100 percent," a KGS official told The Korea Times, Tuesday. "The incident will be carefully and thoroughly investigated to find out what exactly caused it."

In an HFCV, hydrogen is stored in a high-pressure tank and mixed with oxygen from the air in a fuel cell to generate electricity, which powers the vehicle's electric motor.

Based on the location where the explosion occurred, experts said the tank, which is installed in the upper or lower part of a hydrogen bus, was probably not the problem.

"The part is where the fuel cell stack is located. But for now, it is too early to state anything conclusively, given that too little is known about the case," one said.

The bus, manufactured by Hyundai Motor, began operations in August 2022. Officials stated that the driver was en route to an auto repair shop that day after the "F" (fault) icon had appeared on the dashboard on Dec. 21.

"We will faithfully cooperate with the investigation to find the exact cause of the accident," the company said in a statement sent to The Korea Times.

This incident underscores the challenges and safety considerations that come with adopting new energy technologies in transportation, as seen with the adoption of electric cars whose lithium-ion batteries raised safety worries after major fire incidents in recent months.

As of October, 36,989 HFCVs were registered for operation in Korea, up from 29,623 in 2022 and 893 in 2018, according to data from the Ministry of Land, Infrastructure and Transport. The government aims to increase the number of HFCVs operating on the nation's roads to 300,000 by 2030 as part of its efforts to reduce greenhouse gas emissions.

Industry experts also expressed concerns over the possible ramifications of the incident at a time when Hyundai, one of the market leaders, is expanding its hydrogen business overseas.

This all adds to the concerns regarding U.S. President-elect Donald Trump's return to power. During his election campaign, Trump repeatedly expressed his skepticism about HFCVs' safety.

According to a report by the Wall Street Journal, there are 18,300 passenger hydrogen vehicles on U.S. roads, with no reports of explosions or fatalities from these vehicles in the past 10 years.