Shell extract oil. They have benefited Nigeria's economy by making major contributions in taxes and export revenue, providing direct employment for 65,000 Nigerian workers and a further 250,000 jobs in related industries, giving 91% of shell contracts to Nigerian companies and supporting the growth of Nigeria's energy sector. However, oil spills have causes water pollution, soil degradation, and reduction in agricultural production and fishing yields. Frequent oil flares send toxic fumes into the air. Militant groups disrupt oil supply in the delta and oil theft and sabotage are big problems in the region, reducing production levels and costing billions each year.