Gas release 'bang' at Tata's Port Talbot steelworks
Production at Port Talbot steelworks is continuing as normal following reports of a loud bang at the plant.
The "unusual emission" was heard by people living nearby on Thursday but owners Tata said the site was safe.
Natural Resources Wales is investigating and will discuss its findings with the Health and Safety Executive.
It was announced on Tuesday that 400 jobs would be lost at the plant, which employs about 3,800 people.
A Tata spokesperson said: "Following reports of an unusual emission from the site this morning we can confirm that we carried out a successful release of a valve in one of the blast furnaces.
"The site remains safe and our normal production operations continue."
The company said it was "not part of planned maintenance but the team chose to carry out this release of pressure which can happen in certain circumstances, it's a procedural response".