Shell faces $5 billion fine over Nigeria Bonga oil spill

"SNEPCo responded to this incident with professionalism and acted with the consent of the necessary authorities at all times to prevent environmental impact as a result of the incident."

Bonga accounts for around 10 percent of monthly oil flows from OPEC member Nigeria, the continent's largest exporter of crude oil. Production restarted in January.

Oil spills are common in the mangrove creeks onshore Nigeria. Many are caused by sabotage strikes or oil thieves tapping into easily accessible pipelines. Several communities have taken Shell to court over a failure to clean up spills.

A United National Environment Programme report last year said Shell was not doing enough to clean up spills and maintenance of infrastructure was inadequate.

(Writing by Joe Brock; Editing by Dan Lalor)