Finland is at risk of being forced to shut down a large chunk of its heavy road traffic due to sanctions it imposed against Russia, the newspaper Helsingin Sanomat warned on Wednesday. Diesel engines that used by heavy-duty vehicles need fuel with an anti-pollution additive produced using supplies from Russia.

The diesel exhaust fluid (DEF), marketed as AdBlue, is a urea solution that makes the catalytic reactions in modern diesel vehicles which reduce exhaust pollution possible. Sanctions that EU nations imposed on Russian chemical companies mean they cannot import urea from the country, putting a strain on AdBlue manufacturing.

The supply crisis cannot be resolved immediately, Jari Makkonen, the CEO of Finland’s largest producer of DEF, Arom-Dekor, told the newspaper. Finland consumes some 75 to 80 million liters of AdBlue per year, and the reserves may be depleted within weeks, if the crisis is not averted, the executive warned.

Norwegian chemical giant Yara, which is another major producer of AdBlue in Finland, had to stop buying urea from Russia too. It said it hoped to compensate by using its international logistic lines but acknowledged that shortages were possible.