Environmental Protection Agency - EPA "EPA is called a regulatory agency because Congress authorizes us to write regulations that explain the critical details necessary to implement environmental laws. In addition, a number of Presidential Executive Orders (EOs) play a central role in our activities. " Ref: EPA   Currently the EPA of both Nations are working together to keep the air and water clean along the border.  The BorderTransportationSystem by bringing in salt water and using desalinization and purification processes will greatly aid the EPAs in their goals, and at little to no cost to the taxpayers of either nation. Index of ... Environmental Protection Agency (Mexico) EPA Collaboration with Mexico US Environmental Protection Agency U.S.- Mexico Border 2020 Program