Arrowhead is located over one of the most impermeable naturally occurring clay formations in North America. EPA specifications require that Subtitle D landfills are designed to adequately contain waste and provide a barrier between the groundwater through a sophisticated liner and leachate collection system. At our site, Selma Chalk, at depths of over 400 feet, provides an added bonus layer of protection between the lined Subtitle D facility and groundwater, making Arrowhead one of the most environmentally sound disposal facilities in the nation.