Most of some 3400 tonnes of chemicals and oily water that were injected into the reservoir of the Norwegian Sea field over a period from 1999 to 2006 spilled onto the seabed due to a leakage in an injection well, Statoil has found.

It follows a study of the seafloor beneath the Njord A platform carried out by the state-owned operator in late 2010 that uncovered mounds up to 40 metres in radius and more than 2.5 metres high.

Analysis of the formations revealed they were filled with a “significant volume of hydrocarbons” that apparently had leaked from the well, according to the agency.  

However, although Statoil was aware of the findings in early 2011, it failed to report them to the EA before June this year.

“We view this spill as serious and are critical to the fact that it took more than two years from the time at which the results of the seabed study were available until we were notified. The company has a duty to report such spills immediately,” said agency director Ellen Hambro.

A Statoil spokesman admitted it has taken too long to inform the agency of its results from the analysis, while pledging that the company’s reporting routines would now be sharpened.

“It has taken time to determine the possible causes of the leak, as well as data gathering and analysis,” spokesman Ola Anders Skauby told newswire NTB.

“Generally, we have good routines for notifying the authorities but in this case it took too long for us to inform them.”

The company has now been given a 20 August deadline by the agency to provide an assessment of its findings from the seabed study and inform it of proposed follow-up action.