An explosion takes place at a port in Ningbo, China, Aug. 9, in this still image obtained from a social media video. Taiwanese shipping firm Yang Ming Marine Transport said its cargo ship YM Mobility, caught fire at the Ningbo-Zhoushan Port. Reuters-Yonhap

HMM, the largest container shipping company in Korea, is facing a dilemma as to whether to continue transporting electric vehicles (EVs) and batteries containing lithium due to safety concerns.

Amid the recent trend of local car ferries refusing to transport EVs to mitigate fire risks, attention has been focused on whether HMM will put all types of battery-powered vehicles on its prohibited cargo list.

Last year, HMM decided to allow the shipment of vehicles and equipment using batteries made by five Japanese firms — Panasonic, Blue Energy, Maxell, Fuji Denki Kagaku and Toshiba.

Previously, the shipping firm only allowed Korean batteries made by LG, SK and Samsung.

At that time, HMM also decided to permit the use of dry containers for transporting battery-equipped vehicles instead of refrigerated containers, which are typically used for temperature-sensitive goods.

"Lithium-ion batteries are still acceptable only in refrigerated containers," an HMM spokesperson said.

However, the shipping firm has banned the shipment of all lithium metal batteries made by Aricell, since a fire at the battery maker's factory in Hwaseong, Gyeonggi Province, killed 23 workers in June.

Additionally, some foreign news outlets fueled fears over HMM's transportation of batteries by sea.

They reported that batteries inside HMM's container caused an explosion on Taiwanese vessel YM Mobility on Aug. 9, despite the Korean firm's claim that it did not load batteries onto the container.

"We are closely monitoring the situation and now in continuous coordination with the relevant stakeholders, Ningbo Terminal and the vessel's operator — Yang Ming — to minimize any potential impact on our operations," HMM said in a customer advisory on Aug. 12.

On Aug. 8, the Ministry of Oceans and Fisheries recommended that an EV's state of charge (SoC) should not exceed 50 percent during transportation by sea, citing several fires on foreign car carriers, which are presumed to have resulted from EVs.

The ministry also asked ferry owners to restrict the shipment of EVs with accident histories.

Following a recent fire caused by a Mercedes-Benz electric sedan at an Incheon apartment complex's parking garage, which burnt hundreds of other vehicles and damaged the building, some ferry owners even started rejecting the shipment of all kinds of EVs, regardless of their SoCs and accident histories.

H Ferry, which operates car ferries connecting Uljin County with Ulleung Island in North Gyeongsang Province, announced last Monday that it would temporarily stop the shipment of EVs starting from Sept. 1.

"We will stop the shipment of EVs until we are perfectly equipped with fire apparatuses to extinguish EV-caused fires," the company said in its notification.

Car ferries connecting Tongyeong in South Gyeongsang Province with neighboring islands have also refused to ship EVs since Thursday.