The 500 million tons of manure waste created by factory farms each year are damaging the health of animals and people - and no one is regulating it, two new lawsuits allege.

A coalition of groups has filed the suits against the U.S. Environmental Protection Agency (EPA) for failing to address air pollution created by the country's 20,000 factory farms.

The lawsuits state that the EPA has failed to respond to two petitions, filed in 2009 and 2011, asking the agency to address factory farm pollution. The first petition asked the EPA to classify factory farms as a source of pollution under the Clean Air Act, while the second petition called for health-based regulations for unsafe levels of ammonia, a chemical released by factory farms that has been shown to have adverse effects on human health.

Now, the two lawsuits call on the U.S. district court in Washington, D.C., to force the EPA to respond, and to regulate toxic levels of air pollution from factory farms, Tarah Heinzen, an attorney for the Environmental Integrity Project, told reporters on a conference call on Wednesday.

"[Factory farming] is a large and growing industry that has escaped environmental protection for decades," she said, noting that the industry produces three times the waste created by humans every year. The waste is usually placed in massive cesspools and then sprayed on cropland. A study released this week shows that much of this fecal matter is carried by the wind and travels over large distances, carrying with it genetically resistant superbugs that can be harmful to human health.

According to Keeve Nachman, Ph.D., the director of the Food Production & Public Health Program at the Johns Hopkins Bloomberg School of Public Health, ammonia and hydrogen sulfide emissions from factory farms have been associated with higher risks of asthma, heart attacks and gastrointestinal problems.

Rosie Partridge, a rural Iowa resident whose home is surrounded by industrial hog operations, told reporters that sometimes the stench of manure is so bad that she and her husband must leave their house for days on end, adding that she is "certain it is affecting our health."

For animals, the problems are even worse, and "should be alarming to anyone that cares about animal welfare," Jonathan Lovvorn, chief counsel for animal protection litigation for The Humane Society of the United States, told reporters.

Living in tight quarters with poor air quality, animals are the first to suffer. They often die from injuries or from poor living conditions like overcrowding and a lack of clean air. When ill or injured, they're often brought to a "compost pit" to die - another source of pollution that the lawsuits say the EPA needs to remedy now.