Fresh Kills is one of the world's largest domestic landfills and was slated for capping in the late 1990s. Two of four mounds were capped in 1997, but the remaining two were left open for dumping until 2001 when they were filled with excavated material from the September 11 tragedy. Plans to cap the remaining two mounds and turn the entire site into a park and monument for 9/11 are under way. The cap will consist of 5 layers and a landfill gas collection system will be used to generate domestic energy. In this case the use of green remediation will not only prevent the unnecessary expenditure of energy, but will in fact, produce new energy.