Except for the Linbro Park which was closed in the year 2006, the sites are still operational. Studies have proven that operating sites yield more landfill gas than closed ones. Gas can be harvested while a landfill is still operational and up to 50 years after closing the site. Once a landfill has been closed, it will be rehabilitated in line with the "end use closure permit". It could become anything from a new park to a cricket pitch or a golf course.