UP TO 150 workers will cause pay pain for 11,000 of their colleagues and will put Bechtel's $80 million Curtis Island LNG projects at risk when they strike.
With at least 5000 Gladstone workers on the island, negotiations on a new workplace agreement have come to a standstill.
The disagreement is not about wages - Bechtel is offering a 13% pay increase - but rather lifestyle conditions such as workers wanting a shorter rotation roster and travel times.
But Bechtel management says it has to maintain the current roster as the entire foundation of the three major gas projects had been built around a four-week-on, one-week-off rotation roster.
The Australian Workers Union resolved in May to support the offer, which needs 50% plus one vote of 7000 employees to get it up, but this week the Fair Work Commission endorsed members from the Construction, Forestry, Mining and Energy Union to take protected industrial action against Bechtel.
CFMEU divisional branch secretary Jade Ingham said fly-in fly-out workers spend up to 29 days away from their families on 4/1 roster which puts enormous pressure on family relationships.
"It's not just about money. Bechtel refuses to acknowledge the Queensland industry standard roster," he said.
"It is causing a great deal of stress for our members and their families."
Bechtel Gladstone general manager Kevin Berg said rostering could not change this far into the projects.
"The entire foundation of the projects - the concept, scheduling, funding - has been built around a 4/1 rotation, to make that shift (to 3/1) is a huge impact on the number of people needed to maintain the workforce," he said.
"We're willing to go in that direction but not during the course of these projects.
"Our workers have been exceptional during all of this, we've still been able to maintain our operations throughout the voting etc, they've continued to report to work without interruption."
CFMEU needs to give three days' notice before protected industrial action is attempted. Bechtel can then lock out any workers or sections of people unable to continue their work due to the action.
Workers who voted down the agreement for the second time last month voted themselves out of negotiated back pay to May 1.