The Bangkok metropolitan area, which consists of the Bangkok Metropolitan Administration (BMA) and the four surrounding provinces (Nonthaburi, Pathum Thani, Nakhon Pathom, and Samut Prakan), holds about 20% of the national population and over half of the country's factories. Due to a lack of treatment facilities, increasing volumes of hazardous substances generated by the thriving industrial activities have caused serious dumping issues. Unless treatment facilities are built and institutions starts to regulate strictly, environmental contamination caused by hazardous waste threatens to become Thailand's worst environmental problem in the future.