Hundreds of people inhabiting areas close to oilfields in Assam are being exposed to serious halth hazards with the country's two largest exploration companies discharging toxic effluents from drilling sites and indiscriminately flaring natural gas, endangering humans, flora and fauna. Experts says oil pollution and the impact of gas flaring by Oil India Limited (OIL) and the Oil and Natural Gas Corporation (ONGC) in eastern Assam's Dibrugarh districts have assumed 'alarming proportions'.