Workers at Chevron Corp.-operated liquefied natural gas facilities in Australia could begin industrial action from Friday if a final round of talks fails to resolve a long-running dispute on pay and conditions.

Read More: Chevron LNG Talks Resume Friday as Union Poised to Begin Strikes

Strikes are scheduled to begin from 1 p.m. Perth time across the Gorgon and Wheatstone plants and the Wheatstone offshore platform in Western Australia. The sites together supplied about 7% of the world’s LNG last year.

While the impact of strikes may be limited initially, as demand is currently weaker in Europe and Asia, any prolonged disruption would threaten supplies for the peak northern hemisphere winter season and likely push up prices.

According to documents seen by Bloomberg, unions have notified Chevron that action from Friday could include:

• Work stoppages in one-hour blocks for periods of between 3 hours to 11 hours each day
• A refusal to carry out: overcycle work, or performing duties during a period that would otherwise be time off; unpaid overtime by some workers; a transfer to another work site; assignments at a higher function level; night shifts or call out duties by some staff; participation in some training and instruction programs; some work on days designated for travel

A planned escalation if no agreement is reached by Sept. 14 would then effectively halt LNG exports, with workers then also refusing to:

• Facilitate mooring of tankers or vessels; work on loading of vessels with LNG or condensate; take hydrocarbon or amine samples or perform other laboratory analysis; handle faults or restarts related to some equipment, including items used for LNG production; carry out equipment calibration

Unions currently plan the following work stoppages, according to the documents:

• Gorgon: 4 hours on Sept. 8, 11 hours on Sept. 9, 10 hours from Sept. 10 to Sept. 13
• Wheatstone Downstream: 4 hours on Sept. 8, 11 hours on Sept. 9, 10 hours from Sept. 10 to Sept. 13
• Wheatstone Platform: 2 hours on Sept. 8, 4 hours from Sept. 9 to Sept. 13, 1 hour Sept. 14

Here are the key dates so far in the dispute:

• July 26: Australia’s Fair Work Commission, a labor regulator, authorizes the Australian Workers’ Union and the Communications, Electrical, Electronic, Energy, Information, Postal, Plumbing and Allied Services Union of Australia to hold ballots of members at Woodside’s North West Shelf operations on industrial action
• Aug. 9: Almost 150 Woodside workers vote in favor of potential action
• Aug. 10: The commission approves requests by the AWU and CEPU to hold ballots on action among members at Chevron’s Gorgon LNG facility. Separately, the regulator approves both unions to hold votes among workers at the Wheatstone downstream LNG facility
• Aug. 14: Requests by the AWU and CEPU to hold ballots of workers at Chevron’s Wheatstone platform on industrial action are also approved
• Aug. 15: Talks take place between Woodside and unions on disputes at the North West Shelf operations
• Aug. 18: A ballot of workers at Chevron’s Gorgon and Wheatstone downstream facilities begins
• Aug. 21: Voting among workers at Chevron’s Wheatstone offshore platform opens
• Aug. 23: Woodside avoids strikes after a 15-hour meeting with union results in an in-principle agreement. If a deal hadn’t been reached, strikes would have begun from Sept. 2
  • Chevron puts forward a new enterprise agreement — a package of revised pay and conditions — to employees at Gorgon and Wheatstone facilities
• Aug. 24: Workers at Gorgon and Wheatstone downstream plants vote in favor of enabling strikes if a deal isn’t made
• Aug. 28: Employees at the Wheatstone platform vote in favor to enable strikes and unions give Chevron the required seven working days’ notice for industrial action
• Sept. 1: Chevron workers reject the proposed enterprise agreement; producer applies to the Fair Work Commission for assistance in handling the dispute
• Sept. 5: Union officials say action at Chevron sites would escalate to two weeks of 24-hour rolling outages from Sept. 14 if no progress is made in talks.
• Sept. 7: Workers delay the start of partial strikes at the Gorgon and Wheatstone LNG sites to allow talks on a potential deal to continue
• Sept. 8: Chevron and union officials meet for final scheduled meeting ahead of a 1 p.m. Perth time deadline for industrial action to begin
• Sept. 14: Union members at Chevron sites to escalate to 24-hour rolling outages if no resolution reached