Trade union Unite has confirmed a recognition agreement ballot vote, which had a 78 per cent overall turnout, was won on an 83 per cent Yes vote.
The vote, which began on October 1 and concluded on October 21, means the trade union can now negotiate on behalf of the workforce.
The Grangemouth complex is considered one of Scotland’s most important industrial sites, contributing 4 per cent of Scottish GDP and approximately 8 per cent of its manufacturing base.
Howard Beckett, Unite assistant general secretary, said: “I am delighted that after a long process Unite has emphatically won the trade union recognition ballots at Ineos.
“The margin of the result and the confidence shown in Unite will now enable us to collectively bargain on behalf of the entire workforce.”
Pat Rafferty, Unite Scottish secretary, added: “I want to take this opportunity to thank all those involved, in particular our Unite representatives at the Grangemouth complex who through their determination and resilience have made this result possible.”