Experts are trying to work out what caused a substantial fire at part of King’s Lynn Port.
The blaze broke out at a Lynn Shellfish workshop at Alexandra Dock causing a lot of damage to the building.
People were advised to stay away from the area when the fire broke out and there was a 200m cordon put in place to keep the local community safe.
Fire crews, police and ambulance staff were called to the blaze, which was complicated to deal with because of gas cylinders in the workshop creating the risk of an explosion.
Compressed foam was used to bring it under control and no one was injured.
Fire-crew stayed at the scene for several hours to keep the area safe and ensure the gas cylinders pose no further risk.
Norfolk Fire Service will work with Lynn Shellfish and the port to find out a cause for the incident, and will carry out a full investigation into the blaze.