Striking workers at Phillips 66’s Humber refinery have returned to work after three days of industrial action.

About 450 contract workers went on strike on Monday claiming they had safety concerns, but Phillips 66 said the operation of the plant has not been affected by the action.

On Wednesday Phillips 66 said : “The workers have cited concerns over safety, which is the Humber Refinery’s number one priority. Following a recent vapour release on the 5th November, refinery management stopped all work for two hours and met face-to-face with every on-site contract company and their staffs to communicate what occurred and to reinforce Phillips 66’s commitment to safe operations.”

It said the vapour release occurred during routine maintenance and its emergency response team and an ambulance were called. As a precaution two contractors were taken to the local county hospital and they were later released to return to work.