U.S. livestock generate over 1 billion tons of manure each year, equal to the weight of over 3,000 Empire State Buildings. In factory farming operations, waste is often held in open-air manure lagoons or pits, covered buildings, or dry stockpiles. Manure and other wastewater from concentrated animal feeding operations (CAFOs) can release pollutants such as nitrogen and phosphorus, organic matter, sediments, pathogens, hormones, and antibiotics into the environment. Spills, overflows, excessive rain, leaks, runoff, and infiltration can all cause these pollutants to make their way into U.S. waters, including into the ones we use for recreation and drinking water. This pollution can have a wide range of adverse effects, such as:

Illness from pathogens such as E. coli, Salmonella, and Campylobacter
Facilitation of antibiotic resistance and increased antibiotic-resistant infections
Fish kills and other wildlife mortality from oxygen depletion, ammonia toxicity, and cyanobacteria from harmful algal blooms
Greenhouse gas emissions, contributing to climate change
Increased soil and water salinity
Decreased biodiversity
Trace elements and metals toxicity (i.e., arsenic, lead, and boron)

Under the Clean Water Act, the Environmental Protection Agency (EPA) regulates pollution from CAFOs by issuing National Pollutant Discharge Elimination System (NPDES) permits. While all 21,000+ CAFOs across the country are subject to at least some EPA regulations, only a fraction of them have NPDES permits. The sheer number of CAFOs and the level of constant monitoring and maintenance required to identify pollution discharges is cause for concern. But the lack of permits calls into question how much the EPA actually knows about the nation’s CAFOs and what they discharge into U.S. waters.