Meat and dairy production in the United States today looks very different than it did just a few decades ago. As recently as the 1980s, most animals were raised on small, independent farms. Now, millions of pigs, dairy cows, chickens, and turkeys are kept in close confinement at industrial-scale concentrated animal feeding operations, commonly known as Large CAFOs.

According to the U.S. Environmental Protection Agency (EPA), there are more than 21,000 Large CAFOs across the United States. Each of these facilities confines hundreds or thousands of animals — at least 700 mature dairy cows, for example, or 2,500 pigs weighing 55 pounds or more. Many Large CAFOs substantially exceed these size thresholds — for example, the median Large dairy cow CAFO confines 1,200 cows, while the median Large swine CAFO confines 4,588 pigs — and they all generate staggering quantities of waste.

As of 2012, Large CAFOs generated 404 million tons of manure — that is, over 20 times the amount of fecal wet mass produced by all human beings in the United States. In fact, the amount of animal urine and feces from individual Large CAFOs often exceeds the amount of sanitary waste from entire cities. And there’s no question that Large CAFOs are industrial outliers among U.S. farms; although these facilities make up fewer than 1% of farms (and only about 7% of all industrial animal operations), they generate one-third of all farm manure.

The Clean Water Act requires CAFOs to obtain permits before discharging manure and other pollution into our nation’s waterbodies. In practice, however, EPA and most state agencies rely on CAFO owners to determine whether a particular CAFO discharges pollution — in effect, allowing the fox to guard the henhouse. Unsurprisingly, this system isn’t working; EPA admits that many polluting CAFOs fail to obtain the necessary permits. In both the top five dairy-producing states and the top five swine-producing states, the majority of Large CAFOs lack permits issued under the Clean Water Act. In fact, EPA estimates that there are 365, 873, and 488 Large CAFOs in Idaho, Indiana, and New York, respectively — but none of these CAFOs hold federal-law permits. As a result of this under-permitting, many Large CAFOs inappropriately escape oversight that would help to protect waterways and people living nearby.

Large CAFOs using wet manure management systems — predominately, Large CAFOs that confine swine and dairy cattle — store animal urine and feces in liquid form, a practice that is especially likely to result in water pollution. But, according to EPA, neither it nor state environmental agencies have the resources necessary to hold individual CAFOs accountable.

That’s why we’re working to flip the script. Together with more than 50 allied organizations, in October 2022, Earthjustice petitioned EPA to adopt a rebuttable presumption that Large CAFOs using wet manure management systems actually discharge water pollution. If granted, the presumption would require those Large CAFOs either to obtain permits under the Clean Water Act or to prove that they’ve successfully implemented protections to prevent pollution.

To support our petition, we collected and summarized decades of scientific research showing that CAFOs — and Large CAFOs, in particular — routinely and predictably discharge water pollution, including nitrogen, phosphorus, disease-causing pathogens, and pharmaceuticals. Exposure to CAFO pollution in drinking water can cause birth defects and the potentially fatal blood condition methemoglobinemia, or “blue baby syndrome,” in infants under six months of age. It also can increase risks for hyperthyroidism, insulin-dependent diabetes, bladder cancer, and ovarian cancer. In addition, federal agencies have acknowledged that CAFO water pollution harms threatened and endangered species, including the Atlantic sturgeon. The presence of under-regulated CAFOs near important waterbodies, such as critical habitat streams for Chinook salmon, coho salmon, and steelhead in Oregon, strongly suggests that other vulnerable species also are at risk.

Our petition also includes personal stories from people who live in communities harmed by CAFO pollution across the country. These community members report that CAFOs create serious water contamination problems, degrade drinking water, and impair opportunities for fishing, boating, and other forms of recreation. For instance, a resident of Duplin County, North Carolina, who lives within three miles of at least 30 CAFOs, including 12 Large CAFOs, was once an avid fisher, but he stopped fishing after he began to catch fish with open sores, which he believes are caused by bacteria and other CAFO pollutants. Despite evidence of widespread water pollution associated with CAFOs, nearly 99% of Large CAFOs in North Carolina claim not to discharge.

In addition to science and personal stories, our petition includes a new report finding that CAFOs cause disproportionate harm to communities of color, low-income communities, and under-resourced rural communities in North Carolina, Iowa, and California’s Central Valley — all areas in which CAFOs are densely concentrated. According to the report, Latinx people are 1.54 times as likely as White people to live within three miles of a Large dairy cow CAFO in the Central Valley. If all people were exposed to CAFO pollution at the same rate, approximately 227,600 fewer Latinx people would be at risk.

EPA’s current approach to CAFO permitting exposes millions of people to harm, in violation of the Clean Water Act, as well as executive orders aimed at advancing environmental justice. Our petition proposes a significant improvement that would expand protections against water pollution, increase transparency, and support better enforcement. It’s time for EPA to act.

All charts and maps by Mustafa Saifuddin, Earthjustice Staff Scientist.