Cooling equipment, such as refrigerators, freezers, dehumidifiers and room air conditioners involve refrigerants and insulating foams that release ozone-depleting substances and greenhouse gases once in a landfill. Older appliances may also contain PCBs or mercury. Newer products (made within the past 10 years) do not contain these toxic materials and use refrigerants and foam blowing agents that are less harmful to the ozone layer, but they still contribute greenhouse gas emissions. Federal law requires the removal and proper disposal of refrigerants but not foam products.