The Problems Over the last 5 decades, 546,000,000 gallons of oil has been spilled without any cleanup. The height of a crayon: A 3 inch layer of oil, the height of a crayon, covers the drinking water. In some places, the oil has seeped 5 meters underground. 40 years In the Niger Delta, the average life expectancy is 40 years. For the rest of Nigeria, it is 55 years. In America, the life expectancy is 80 years. 1 in 8 In the Niger Delta, 1 in 8 people are at risk of dying of cancer. In America, 3 in 10,000 are at risk.