A clean-energy power source got a bit dirty last week in the Irish Sea. A dive vessel crashed into a hulking offshore wind turbine, spilling as much as 10 metric tons of diesel oil in the waters that separate the islands of Ireland and Great Britain.

The dive vessel, owned by Danish firm Offshore Marine Services, was carrying out routine inspection work when an anchor cable broke and the ship slammed into one of 102 turbines installed at the Walney Offshore Wind Farm, the North-West Evening Mail reported.

The U.K.’s Maritime and Coastguard Agency surveyed the crash site and reported that a surface sheen stretching 33 feet wide and 0.7 nautical miles long was trailing the vessel. The agency said that, unlike heavier crude oil, the marine engine oil should evaporate or disperse naturally.

A spokesman for Dong Energy A/S, the wind farm’s operator, said there was no damage to the turbine, the newspaper said.