Shares in Royal Dutch Shell dropped sharply today after it said an oil sheen had been spotted near one of its production areas in the Gulf of Mexico.
The Anglo-Dutch firm said there was no indication that the light sheen originated from wells in either the Mars or Ursa projects but that out of "prudent caution" it was sending a response vessel to investigate further.
However, with BP's Deepwater Horizon disaster of 2010 fresh in the minds of investors, shares in the company dropped 4% on the London market today.
As well as sending the vessel, Shell has requested flights to monitor the sheen, which measures one mile by 10 miles.
It added in a statement: "At this time, the source of this sheen is unknown, and Shell's priority is to respond proactively, safely and in close co-ordination with regulatory agencies. Updates will be provided as further action is taken."
The Deepwater Horizon explosion killed 11 workers and impacted hundreds of miles of coastline after an estimated 4.9 million barrels of oil poured into the sea.