From 9 to 17 November 2021, we carried out an audit of how Equinor has followed up non-conformities and orders pursuant to the PSA’s investigation of the incident involving overpressurisation of sludge cell 11 at Statfjord A. 


In our investigation of the incident, we identified non-conformities involving inadequacies in the process safety system to prevent overpressurisation of sludge cells, a lack of risk and system understanding in the planning of ballast water valve maintenance, a lack of safeguards for safety-critical valves and inadequate system description and operational documentation, as well as one improvement point relating to deficiencies in the company’s own follow-up. 

Equinor was ordered to implement the following measures: 

  1. Review the use of the storage cells on the Statfjord facilities to ensure that sufficient technical and operational barriers are in place, and review the system descriptions and procedures to ensure safe operation of the cells. 
  2. Present a plan for following up the effects of the company’s own measures for correcting the identified non-conformities in the PSA’s investigation report and the action areas in the company’s own investigation report. The action areas in the company’s own report cover the conduct of risk assessments, documentation and procedures, technical upgrading of Statfjord A, and facility-specific expertise and compliance with requirements. The plan must also cover other facilities with a similar design. 


The objective of the audit was to verify that Equinor has implemented measures pursuant to our investigation and the company’s own investigation, such that the technical and operational measures ensure that adequate barriers are in place and that this contributes to learning lessons from the incident. 


No non-conformities were identified during the audit, but we observed three factors that are categorised as improvement points. These concerned: 

  • updating of drawings 
  • updating the operation procedure 
  • system documentation 

Follow-up of previous audit 

In line with our audit notice, as part of this audit, we verified how the participant has addressed previously identified non-conformities and previous orders.  

The following non-conformity and order have been found to have not been addressed in line with the company’s feedback at the meeting of 15 October 2020, and in updates on 29 March and 1 June 2021:  

What happens now? 

We have asked Equinor to give us their assessment of the improvement points observed by 1 February 2022.