Three Nigerian subsidiaries of ExxonMobil have declared force majeure on crude liftings from their respective terminals, the company confirmed with Upstream on Monday.

Mobil Producing Nigeria, Esso Exploration & Production Nigeria, and Esso Exploration & Production (Offshore East) declared the force majeure “due to an industrial action by our in-house workers Union”, the company said.

The subsidiary Mobil Producing Nigeria operates a joint venture with the Nigerian National Petroleum Corporation.

The joint venture operates over 90 offshore platforms at a capacity of over 550 thousand barrels per day of crude, condensate, and natural gas liquids, the company says on its website.

“We will continue to take all reasonable actions necessary to resolve the impasse as soon as possible. The safety of our people, assets and environment remains our top priority,” ExxonMobil said in a statement.