BP has been accused of dumping industrial waste in a marine protected area west of Shetland.
The energy giant is at the centre of an environmental row as it seeks to decommission the floating production vessel Petrojarl Foinaven.
But industry leaders and environmentalists have criticised its move to drop steel pipe “risers” connected to the vessel into the sea as part of the process.
It is feared the move could cause damage to the seabed where protected species of sponge grow.
However, BP says the action does not amount to dumping, as it plans to later remove the material.
It says its activities are “within regulations” and has been approved by regulators.
Green campaigner and councillor Alex Armitage has voiced concerns over the impact oil companies are having.
“The Faroe-Shetland sponge belt is an important marine ecosystem and if BP is to be allowed to operate there, it should be under the strict provision that no dumping of hardware is allowed – instead BP plans to dump tonnes of steel on the seabed,” he said.