A primary concern about the proposed Keystone XL oil pipeline is that a leak would contaminate the Ogallala aquifer, one of the nation's most important sources of drinking and irrigation water. InsideClimate News is republishing this investigative story from ProPublica because it highlights another risk to U.S. aquifers: The EPA is allowing some of them to be used as dumping grounds.

Federal officials have given energy and mining companies permission to pollute aquifers in more than 1,500 places across the country, releasing toxic material into underground reservoirs that help supply more than half of the nation's drinking water.

via EPA Lets Energy Firms Pollute America's Underground Water Supply | InsideClimate News.