The environmental impact of pig farming is mainly driven by the spread of feces and waste to surrounding neighborhoods, polluting air and water with toxic waste particles. Waste from pig farms can carry pathogens, bacteria (often antibiotic resistant), and heavy metals that can be toxic when ingested. Pig waste also contributes to groundwater pollution in the forms of groundwater seepage and waste spray into neighboring areas with sprinklers. The contents in the spray and waste drift have been shown to cause mucosal irritation, respiratory ailment, increased stress, decreased quality of life, and higher blood pressure. This form of waste disposal is an attempt for factory farms to be cost efficient. The environmental degradation resulting from pig farming presents an environmental injustice problem, since the communities do not receive any benefit from the operations, and instead, suffer negative externalities, such as pollution and health problems. The United States Agriculture and Consumer Health Department has stated that the "main direct environmental impact of pig production is related to the manure produced.
Around the world
Australia
Australia is home to one of the largest pork industries in the world with farms across Australia collectively containing over 300,000 pigs but there are high levels of water pollution.
China
Pork is the most popular meat in China. Intensive pig farming leads to smog and water pollution in some Chinese regions. According to the Chinese Ministry of Agriculture, livestock farming is the leading cause of water pollution in the country.
France
Swine farm manure leads to toxic algal blooms in the French region of Brittany.
Netherlands
The Netherlands has one of the densest livestock sectors in the world. In 2019, a Dutch court halted the expansion of pig and other farms to prevent nitrogen pollution, which had led to algal blooms, smog, and soil acidification.
United States
The United States Environmental Protection Agency (EPA) calls intensive farms above a certain threshold concentrated animal feeding operations (CAFOs).
In the 1970s, a series of laws, known as "Murphy's Laws", were passed in North Carolina to eliminate the sales tax on hog farm equipment and to prevent authorities from using authority to prevent and address odor issues. After the passage of Murphy’s Laws and other similar bills, there was a rapid increase in industry in North Carolina, where the population of swine was estimated around 9-10 million. Each of those hogs produces eight times the feces as a human, causing a crucial need for regulation and maintenance for that waste.
Regulation and laws could not keep up with the rapid explosion of the hog farming and spread of CAFOs in the early 2000s, which has caused severe harm and health impacts over time. Furthermore, agencies with jurisdiction over CAFOs are typically environmental or natural resource state-run agencies, as opposed to local health departments. This is an advantage for addressing environmental impacts but a disadvantage for human health concerns, as the majority of local health issues get overlooked by state-run agencies. Additionally, although there are laws and regulations in place, such as the Swine Farm Environmental Performance Standards Act, which prohibits new waste lagoons and mandates that new CAFOs must use technology that will prevent discharge of waste, these regulations do not mandate for existing CAFOs to clean up or regulate the pollutants within their lagoons. These regulations also make it more costly to clean up these wastes and prevent other consequential harms, without actually assisting farms in shouldering these costs, making it difficult for them to actually act on these regulations.
Ag-gag laws have made it even more difficult for farms to be held accountable for their actions, and for communities to have a transparent view of farm operations. These laws forbid the undercover video-taping or documenting of farms without the consent of the farm's owner. These laws are targeted at keeping animal rights and environmental activists away from the most damaging farm operations. These laws emerged in the 90's and are now in effect in North Carolina, Utah, Missouri, Idaho, and Iowa, and is being considered in at least five states. These bills have the potential to exacerbate animal abuse on these large scale farms and CAFOs, as well as threaten community health, social justice, and consumer health by restricting organizations and individuals from sharing pertinent information about the food supply.