The accident occurred during the loading of catalyst into the FCC unit under maintenance, the Polish-owned company reported.
Both victims were employees of Paslaugos Tau, a subsidiary of Orlen Lietuva. According to initial reports, both were Lithuanian citizens.
Audrius Stasiulaitis, the head of communication at Orlen Lietuva, told BNS that there had been no more casualties.
The Fire and Rescue Department told BNS that five fire engines had been sent to the scene but the fire had not broken out. Criminal investigation experts are trying to establish the causes of the explosion.
Orlen Lietuva, the Lithuanian oil refinery owned by Poland’s largest oil concern PKN Orlen, launched maintenance works of fluid catalytic cracker (FCC) unit at the end of February.
These maintenance works are part of preparations for the main turnaround, which will start on 16 April and will continue until 30 May.