Steel company Tata has formally announced it is to separate its UK pension scheme from the business.
It could mean a potential merger between the Indian-owned firm and the German steel producer ThyssenKrupp is more likely to move forward.
The £15bn British Steel Pension Scheme (BSPS) has been a significant barrier to any agreement.
Tata has been in negotiations with pension regulators and trustees of the scheme.
Gary Keogh, multi-unions vice chairman at Port Talbot, said there were “no happy endings” but workers now had options to choose from – joining the new pension scheme, pooling their pot or joining the Pension Protection Fund.