The escape was discovered by an operator investigating the area following a verbal report of an unusual smell. Parts of the plant were closed, the alarm was sounded and personnel were evacuated. No personal injuries have been reported as a result of the incident.

Internal corrosion in a minimum flow line for pump protection in the cracker caused the leak. Statoil has subsequently estimated the leak rate at 0.01 kilograms per second (kg/s). 


The PSA’s investigation has identified four nonconformities. Of these, the most important for the incident was inadequate assessment of changes to operating conditions.

The other three concern deficiencies in maintenance and inspection, inadequate compliance with routines and information transfer for safe operation of the plant, and inadequate understanding of risk and identification of risk conditions when clearing up naphtha-polluted materials.

An improvement point concerning the evacuation alarm was also identified.

Statoil has been given until 23 March 2018 to explain how the nonconformities will be dealt with, and to provide an assessment of the identified improvement point.