A legal, sanitary landfill is a land disposal site for non-hazardous household solid waste, where the waste is spread in compacted layers. Landfills are primarily regulated by state, tribal, and local governments. They are located, designed, operated, monitored, closed, cleaned up, and financed to meet federal standards. 

Two major contaminants in landfills are leachate, which is the liquid from natural moisture that runs through the waste, and landfill gas, which is primarily made of methane. Landfill gas can also include carbon dioxide, nitrogen, volatile organic compounds and hazardous air pollutants such as benzene, toluene, and vinyl chloride.

Human exposure to landfill gas can cause respiratory problems, central nervous system damage, and cancer. Landfill gas can also travel under the soil surface, accumulate in enclosed structures, and catch on fire. 

A legal landfill is different from an unregulated, illegal dump, where wastes are disposed of without a permit. Illegal dumping is also called open dumping, fly dumping, or midnight dumping when materials are dumped in open areas, from vehicles along roads, or late at night. 

Illegally dumped materials can include construction waste, automobiles, auto parts, scrap tires, appliances, furniture, and medical waste. Scrap tires and bulky items may be illegally dumped because they are banned from landfills and their proper disposal may be expensive. 

Illegal dumps can cause not only the same human health risks as landfills, but also other health threats. Rodents, insects, and other disease-carrying pests are attracted to dump sites. Polluted water runoff from dump sites can contaminate wells and other sources of drinking water. Disease-carrying mosquitoes can breed in the rain water that collects inside discarded tires.

This description is based on the information found in the Web links listed with this topic.

Web Links from MedlinePlus (National Library of Medicine)
Environmental Health
Hazardous Waste

More Links
Landfill Gas - Public Health, Safety, and the Environment (Environmental Protection Agency)
Landfill Gases and Odors (Georgia Division of Public Health) (PDF — 141 KB)
Recycling: Frequently Asked Questions (Environmental Protection Agency)
Solid Waste Landfills (Environmental Protection Agency)

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Last Updated: December 10, 2012