26 MARCH 2026 – Equinor has completed its internal investigation into an incident on 29 October 2025, in which personnel at Mongstad were exposed to chemicals. The incident occurred during work on a measuring instrument. A number of measures have been implemented to capture lessons learned.
On 29 October, activity at the Mongstad refinery was high. The plant was preparing for start-up following an extended maintenance shutdown, and as part of this work, a team was assigned to troubleshoot and fill naphtha into a measuring instrument. The task was expected to take around 30 minutes but lasted for more than five hours. Re-evaluation of risk was not performed and led to prolonged exposure. Two employees experienced discomfort afterwards, and one of them was absent from work for a brief period.
“We take this incident very seriously. Everyone shall be safe when working at the plant, and we work every day to ensure this through the planning, execution and follow-up of our operations. After the incident naphtha has been replaced with glycol, which does not emit benzene, in this type of measuring instrument. The report provides us with clear insight into the causes of the incident and lessons to incorporate into our ongoing improvement work at Mongstad, together with employees, the safety service, suppliers and authorities,” says Bernt E. Tysseland, vice president at Equinor Mongstad.
Causes of the incident
The investigation report points to several factors that contributed to the incident. Staff worked in an area with elevated benzene levels for several hours, and the respiratory protection selected did not provide adequate protection in this situation.
In addition, issues relating to the management of the chemical environment are highlighted, and the ramp-up phase after the maintenance shutdown involved high activity and perceived time pressure. This affected the planning and risk assessment prior to the work. No new risk assessment was conducted when the job took longer than planned. Furthermore, the review identified areas for improvement related to the introduction of an updated respiratory protection regime.
Measures to strengthen risk management
Following the incident, several measures have been introduced to strengthen risk management in relation to the chemical working environment at Mongstad. These include enhanced compliance with the protection regime, increased availability of respiratory protection, and further training in the use of benzene and gas detectors. To ensure stronger professional support in the field, a dedicated safety engineer has been assigned to work on improving the chemical working environment at the facility.
The incident is reported to the police by the Norwegian Ocean Industry Authority who will both receive the report from Equinor.
Fact Box 1: About the incident from the investigation report
The investigation describes several factors that contributed to an increased risk of chemical exposure:
- Planning during the period was perceived as challenging and unclear, with perceived time pressure to get the plant up and running again.
- The risk assessment during preparation and execution did not cover all relevant risks.
- The job was assigned to a team that was not sufficiently prepared for the task.
- The filling work was not included in the plant's start-up procedure after the shutdown.
- Naphtha was transported to the measuring instrument in open buckets by operations personnel who did not use respiratory protection.
- The work was expected to take around 30 minutes but lasted for over five hours. Re-evaluation of risk was not carried out, and the exposure was therefore higher and lasted longer than anticipated.
- The investigation identified improvement points relating to the implementation of the protection regime updated in February 2025.
- This contributed to the employees using respiratory protection unsuitable for prolonged exposure.
- Due to necessary clarifications, the case was classified on 19 November and subsequently forwarded to the Norwegian Ocean Industry Authority (Havtil).
Fact Box 2: About the investigation
- The purpose of Equinor’s internal investigations is to understand the course of events and causal factors, and to promote recommendations for learning and improvement.
- The investigation was carried out by Corporate audit and investigation at Equinor.
- The investigation is based, among other things, on 52 interviews with management, staff at Mongstad, technical support, supplier personnel and laboratory personnel.
- The Norwegian Ocean Industry Authority (Havtil) has conducted its own investigations and has reported the case to the police, who are investigating the incident.
- The investigation report from Equinor has been sent to the Norwegian Ocean Industry Authority (Havtil)
- Sections of the reports are redacted due to security considerations.
Fact Box 3: Benzene and Protection Regime
- Benzene is present in several raw materials and products at Mongstad, including naphtha.
- The risk of benzene exposure is managed through monitoring, planning and correct use of protective equipment.
- The aim is always to keep exposure as low as possible.
- The understanding of risks associated with benzene has increased significantly in recent years, which has resulted in lower exposure limits and stricter requirements for both monitoring and control.
- In February 2025, Equinor introduced updated rules for the use of respiratory protection in the event of possible benzene exposure, including a lower threshold for use of such protection.