Landfills are used for the disposal of a variety of solid wastes.  However, due to the many health hazards involved with such massive deposits of sometimes toxic waste, the U.S. federal government has forced many landfills to close.  Even so, two-thirds of waste in the United States currently makes its way to landfills.

Landfills are supposed to be attentive to environmental hazards throughout the course of their operations.  Yet this has not always been the case, and even now landfills can be extremely dangerous.  Still, many landfill problems involve fills established before stricter federal regulations were put in place.  Many of these older fills contain toxic groundwater contaminants, including nitrate, ammonia, solvents, PCBs, and heavy metals.  Once these substances reach groundwater, the contamination can be very damaging, particularly if it reaches drinking water wells. 

Many substances can make their way into drinking water.  These include, but are by no means limited to, bacteria, dissolved salts, heavy metals, petroleum hydrocarbons, volatile organic compounds, and pesticides.  Any number of health problems may therefore result, including leukemia.  Contaminated groundwater can also cause contaminated air in surrounding homes, and this too poses a variety of health risks.

Surface water run-off from landfills can also be contaminated and very dangerous.  Run-off can make its way into nearby bodies of water or on to private property; depending on the chemicals it contains, it can then cause harmful erosion.  In instances of closed landfills that have been improperly capped, direct contact with the toxic waste can occur as well.  Another major danger from landfills is that decomposing waste produces methane, an odorless gas; upon making its way into nearby basements, methane can cause explosions.  Even the regular unpleasant odors from landfills can pose problems, e.g. by causing eye irritation or respiratory ailments.

A game to reduce waste in landfills