Spectacular fiery show at Marsden Point refinery

The welding on a valve could be the issue behind a spectacular fiery show at NZ Refining at Marsden Point.

The welding on a valve could be the issue behind a spectacular fiery show at Marsden Point on Monday night.

NZ Refining spokesman Greg McNeill said the site encountered an issue during the restart of the hydrocracker and as a safety precaution, the unit was shut down.

A huge fireball was seen at the plant, 30km southeast of Whangārei about 10pm on Monday, as the refinery's stack flared.

"The flaring is a safety precaution to allow the safe venting of refinery gases during the shutdown of this unit," McNeill said

The NZ Refining firefighting team was ready to act but was not needed. A weld failure on a newly installed isolation valve could be the problem.

McNeill said everyone on site was safe, the plant was not damaged and plans were being made for the repair and subsequent restart.

He said members of the public would have seen the flaring and yesterday a plume of steam was expected. People may be able to smell hydrocarbons from time to time.

Staff were monitoring the process at the refinery fence line to ensure the public remained safe.

"Our team is working on getting the unit back safely and will keep you posted on our progress."