Equinor (EQNR) said Tuesday its Equinor Refining Norway unit received a fine of 220 million Norwegian kroner ($21.7 million) and a confiscation claim of 500 million kroner for historical pollution control violations.

Norway's National Authority for Investigation and Prosecution of Economic and Environmental Crime imposed the fine concerning past emissions and discharges that the company said it reported and investigated.

Equinor Refining plans to challenge the penalty, rejecting allegations it "failed to fulfill its duty of proper maintenance of the plant over several decades" and claims that it "saved costs through inadequate maintenance."

Shares of the company were 1% lower in premarket activity.