Poland’s energy ministry said it has decided to release mandatory oil reserves following the suspension of contaminated oil deliveries from Russia in April, to secure regular output at local refineries.

The ministry would release a total of 800,000 tonnes of mandatory oil reserves, a spokeswoman said in an email sent to Reuters on Thursday, according to Reuters.

Poland, Germany, Ukraine, Slovakia and other countries halted oil imports via the Druzhba pipeline last week after finding contaminants that can damage refinery equipment.