SEOUL (Reuters) - South Korea is urging automakers operating in the country to disclose the manufacturer of batteries used in electric vehicles (EV) as authorities try to calm fears over fires involving EVs, after a recent blaze in an underground parking lot that took eight hours to put out.

Experts say more can be done, however, noting that while identifying the specific maker of batteries used in EVs would give consumers more choice, there is a lack of definitive data on which brands are most prone to fires.

Here are some details on what we know about EV fire safety concerns:

WHY HAVE EV FIRES HIT THE HEADLINES IN SOUTH KOREA?

A fire on Aug. 1, which appeared to start spontaneously in a Mercedes-Benz EV using Farasis Energy's batteries parked in the city of Incheon, took more than eight hours to put out, destroying or damaging about 140 cars and forcing some residents in the apartments above to move to shelters.

Images of the aftermath of the blaze showed dozens of charred vehicles with only metal frames remaining.

Officials said the fire was made worse because equipment such as sprinklers in the parking lot did not work properly.

The blaze pushed the government to hold a series of meetings to draw up measures to prevent such incidents.

WHAT DOES DATA SHOW ABOUT EV FIRES?

EVs do not appear to catch fire nearly as much as recent headlines might suggest.

In the United States, EVs caught fire at a rate of 25 per 100,000 units sold, compared with 1,530 for gasoline-powered vehicles and 3,475 for hybrids, according to a study conducted by insurance company AutoInsuranceEZ published in 2023 using data from the National Transportation Safety Board.

South Korea saw 72 fires involving EVs last year, up 200% from 24 in 2021, according to the National Fire Agency.

The number of fires per 10,000 EVs was 1.3 last year in South Korea, compared with 1.9 for internal combustion engine-powered vehicles, according to the Science & Technology Policy Institute.

Nearly one in five cars sold globally in 2023 was electric, according to the International Energy Agency, with nearly 14 million sold, mostly in China, Europe and the United States. This took the total number of EVs on the road to 40 million.

WHY CAN EV FIRES BE HARDER TO TACKLE?

Auto experts say EV battery fires burn differently than fires in internal combustion engines, often lasting longer and being harder to extinguish as they have a tendency to reignite.

EVs are propelled by lithium-ion batteries, which can store a massive amount of energy. If a battery is breached, or has a design problem or internal short-circuit, a fire can result from a chain reaction known as thermal runway.

The flammable chemicals can release their own oxygen as they burn, allowing EV fires to reignite hours or even days after they appear to have been put out, say experts.

WHAT MAKES SOUTH KOREA PARTICULARLY VULNERABLE TO EV FIRES?

South Korea is one of the most densely populated nations in the world. More than 60% of its 50 million people live in apartments or other multi-household dwellings, government data shows, often using underground parking with EV charging stations.

"South Korea's somewhat unique environment, such as a large number of cars parked in a closed space at the same time, could make it more difficult to put out a fire," said Jegal Yeong-soon, professor at Kyungil University's School of Fire Safety.

WHAT MEASURES CAN BE TAKEN TO REDUCE RISKS?

In recent days, companies such as Hyundai Motor ( HYMTF ), Mercedes-Benz Korea, Kia Corp ( KIMTF ) and Volkswagen Korea have started identifying their battery suppliers.

Analysts say this does not go far enough to reduce fire risks, highlighting a need for better battery management systems, as well as more sophisticated and early warnings and stronger fire safety measures for parking lots.

Moon Hak-hoon, an automotive engineering professor at Osan University, said authorities should also create a certification scheme to help guarantee the safety of EV batteries.

Kim Jonghoon, a professor at Chungnam National University studying EVs, said preventing EV owners from fully charging batteries could cut fire risks as there were more cases of fires when the battery is over 90% charged, though he notes carmakers looking to achieve longer ranges will likely oppose this.

Kim sees a potential short-term negative impact on South Korean EV sales because of concerns over the recent fires, but is optimistic about the transition to EVs longer term.

The number of applications by people wanting to sell EVs in South Korea rose 184% between Aug. 1 to Aug. 7 from a week earlier, according to used-car trading platform K Car .