The investigation begins in Iraq, in the oil fields which extend from Nahr Umar to Halfaya. Black gold is a sensitive subject, a notorious source of conflict throughout Iraq’s recent history. This region is as rich as it is dangerous. We meet local people who are convinced that pollution from flares at the oil refineries is responsible for a rise in illness, including breathing difficulties and childhood cancer. The site is vital for Iraq. It supplies energy to more than half the country.