BP has shut 12 producing wells at its Alaskan operations after workers told the Financial Times the wells were leaking oil or diesel insulating agent.
BP is to appoint an ombudsman to investigate employee concerns
The British oil firm said they had been shut while the allegations were being investigated.
The 12 wells being shut at Prudhoe Bay, North Star, and Milne Point fields pump a combined 8,000 barrels of oil a day.
BP's move comes as the firm could face a criminal investigation in the US over a massive oil spill in Alaska in March.
It is under investigation by a grand jury over the spill of some 267,000 gallons (1 million litres) discovered at the Prudhoe Bay field, and the largest ever on Alaska's North Slope region.
The leaking liquids in the latest claims are a freeze protection material used in well cellars.
The material known as "arctic pack", is usually crude oil or diesel fuel added to the well.
None of the leaked material had reached the Arctic tundra, the firm said.
The recently appointed head of BP's US operations, Robert Malone, has made cleaning up the firm's public image a top priority.
BP says Mr Malone has ordered that an ombudsman should be employed by September to independently deal with staff concerns about environmental or safety issues.