Panic buying has sparked shortages at filling stations in South Korea.
But it's not fuel itself that's running short.
Instead, there's a shortage of urea, which is added to diesel to cut emissions from trucks and factories.
Around two million vehicles - mostly trucks - are required by South Korean law to use the additive, according to experts.
Without it, commercial transport and some energy industries could grind to a halt.
Authorities announced Tuesday (November 9) that a military oil tanker was on its way to Australia this week to airlift out 27,000 liters of urea solution.
In Seoul, one driver described the problem.
"The situation is really bad. I drove about 70 kilometres to a petrol station to just get urea for my truck and there were long queues of vehicles and my turn didn't come, so I just left empty handed."
97% of South Korea's urea imports came from China in the first nine months of the year.
But Beijing introduced a new export requirement in October to boost supplies in its domestic market - leading to South Korea's shortage.
Refiners have warned the lack of urea is threatening to stop delivery trucks carrying gasoline and other fuels to local filling stations.
It could have an even greater impact on the country's industrial sector.
Environmental regulations mean that some manufacturers must use urea or face penalties.
South Korea - whose President said there is no need for 'excessive concern' - is now in talks with a number of countries to acquire up to 10,000 tonnes.
That would be enough to make about 30,000 tonnes of the critical diesel additive.