This report presents the ndings of a unique investigation into the operational practices of the oil industry in the Niger Delta. It is the result of hundreds of hours of work by more than 3,500 Amnesty International supporters and activists, based in 142 different countries. They took part in Decode Oil Spills, a ground-breaking online project for crowdsourcing research...According to the company JIV [Joint Investigation Visit] forms, the majority of spills during this period were caused by “third party interference.” Shell reported that more than 80% of spills along its network during this period were caused by sabotage and theft. Eni reported that 89% were. The companies say that this means that the majority of spills and resultant pollution were not their fault...The Decoders project reveals that while oil spills have occurred over the whole network of Shell and Eni’s oil wells and pipelines, a handful of spill “hotspots” were repeatedly affected. As these acts were predictable, Shell and Eni should have taken appropriate measures to help prevent them, such as stepping up surveillance patrols...Amnesty International’s analysis of JIV forms completed by the government regulator, the National Oil Spill Detection and Response Agency (NOSDRA), found that between 2014 and 2017, its agents had warned Eni on 162 different occasions to improve surveillance along the pipeline to prevent further spills...