Equinor (EQNR) said Thursday it has completed an internal investigation into a chemical exposure incident at its Mongstad, Norway refinery in October 2025.

The company said personnel were exposed to elevated benzene levels during work on a measuring instrument, with two employees experiencing discomfort and one briefly absent from work.

The investigation identified contributing factors including inadequate respiratory protection and operational pressure during a post-maintenance ramp-up phase, Equinor said.

The company said it has implemented measures including replacing naphtha with glycol in measuring equipment, increased availability of respiratory protection, and further training in the use of benzene and gas detectors.

Equinor shares were 1.1% higher in Thursday premarket activity.