A waste pond or chemical pond is a small impounded water body used for the disposal of water pollutants, and sometimes utilized as a method of recycling or decomposing toxic substances. Such waste ponds may be used for regular disposal of pollutant materials or may be used as upset receivers for special pollution events. Often, chemical ponds themselves are addressed for cleanup action after their useful life is over or when a risk of groundwater contamination arises. Peak usage of waste ponds in the United States occurred in the period 1955 to 1985, after which the environmental risks of pond technology were sufficiently understood, such that alternative technologies for waste disposal gradually began to displace many of the waste ponds. Waste ponds often have pond liners, such as concret