Nigeria, June 3 -- British multinational energy giant Shell continued operating one of its major oil pipelines in Nigeria for years despite internal warnings about environmental risks and infrastructure concerns, according to newly disclosed company documents.

The documents, obtained by the BBC through ongoing litigation in the United Kingdom, include emails, technical assessments and internal presentations showing that Shell executives repeatedly expressed concerns about the safety and condition of the Nembe Creek Trunk Line (NCTL), a key pipeline transporting crude oil from inland oilfields to export facilities.

The revelations emerge amid renewed scrutiny of decades of environmental pollution in Nigeria's Niger Delta, where repeated ...