Offshore mining and the extraction of oil and gas reserves from the continental shelf are a marine pollution threat. The North Sea hydrocarbon industry, for instance, has left hundreds of piles of drill cuttings on the seabed contaminated with metals such as boron and cadmium as well as diesel used to lubricate drilling. There is an estimated 2 million tons of this debris, spread across hundreds of square kilometres.

Summitville mine, Colorado, USA, constructed a $4.7 million state reclamation bond. Avalanches damaged the poorly designed collection ponds at the mine, and cyanide-contaminated water leaked into streams. The mining company declared bankruptcy. This left the citizens of Colorado and the EPA (i.e. the rest of the nations taxpayers) with estimated cleanup costs of at least $100 million, of which the bond covers less than 5%. Allowing waste ponds in a potential avalanche zone was the first mistake. The poor design of the ponds themselves was the second. But even the best available technology does not prevent worst case scenarios from taking place.