Supplies of diesel exhaust cleaning liquid in Germany were thrown in doubt on Wednesday as one of the country’s largest makers of the AdBlue-branded fluid said it was running out of stock after stopping production due to high natural gas prices.

Germany’s biggest ammonia and urea maker SKW Piesteritz, which relies on natural gas as its key feedstock, stopped producing about two to three weeks ago to avoid further losses and is about to sell off its remaining AdBlue inventories, a spokesperson told Reuters.

“We are running dry. We are emptying our inventories because we are no longer producing,” he said.

AdBlue is needed in modern diesel engines of trucks and buses to comply with nitrogen oxides exhaust rules. Germany is particularly reliant on AdBlue because of the large proportion of diesel-powered passenger cars on its roads.

The energy crisis facing Europe has grown more acute after Russia’s Gazprom indefinitely suspended gas supplied through the Nord Stream 1 pipeline to Germany last week.

“We have not yet been able to observe a real shortage, but we are prepared for this and will turn to measures if necessary to keep this important substance available,” an economy ministry spokesperson said at a regular news conference in Berlin, adding the government would monitor the market, among others that rely heavily on gas.

Imports from abroad may be an option and producers might qualify for emergency state funding, he added.

In the AdBlue market, SKW Piesteritz competes with companies including BASF and Norway’s Yara, which run large plants in Germany for ammonia and related substance urea.

These basic chemical feedstocks also play a key role in the manufacturing of nitrogen fertilisers as well as some engineering plastics. The chemical reactors also yield high-purity carbon dioxide (CO2) as a byproduct, which is needed by the meat and fizzy drinks industries.