After the base was closed, Puerto Rico Governor Sila Calderon requested Vieques be placed on the U.S. National Priorities List as a designated superfund clean-up site. the EPA has listed the following contaminants and ordnances at the western portion of the naval station: unexploded ordnance UXO, remnants of exploded ordnance, mercury, lead, copper, magnesium, lithium, napalm, depleted uranium along with other unspecified materials. In addition to these, the eastern portion of the site "may also include" polychlorinated biphenyls (PCB), solvents and pesticides.