A Wicimico County resident protests the industrialized poultry farm proposed near her home early last year. (Photo: Ralph Musthaler/Delmarvanow.com)

In a recent challenge to the Maryland Department of the Environment’s (MDE) approval of an industrial poultry facility (also known as a large Concentrated Animal Feeding Operation, or CAFO) in Worcester County, MDE stated that its review of these permits must meet only minimal requirements to protect water quality.  The MDE claims that it does not review these operations for their other impacts, such as groundwater and air pollution, even allowing poultry waste to discharge into local waters in certain circumstances.  As a result of MDE’s failure to regulate these massive operations, local residents have begun pressing their county councils to protect them.  

This summer, Wicomico County held a public hearing to discuss a proposed increase to the minimum required setbacks for concentrated animal feeding operations (CAFOs). The old county rules required a setback of only 100 feet from property lines. [1] This fall, the council passed new regulations that include a 200 foot setback from all property lines and a minimum 400 foot setback between poultry houses and any building not on the same property.  The requirements also include a 500 foot setback between exhaust fans and homes or buildings on neighboring properties, and 600 feet if the fans are facing toward those buildings.

As CAFOs increase in size and number on Maryland’s Eastern Shore, the additional pressure on water and air resources in the area have adversely affected a growing number of private residences. The debate gripping Wicomico County is demonstrative of local residents and local governments becoming aware and concerned about the effects CAFOs have on the environment and human health, not to mention property values. Citizen groups have taken on the poultry industry in Maryland to create larger minimum setbacks, oppose the construction of new CAFOs and impose other regulations on an already under-regulated poultry industry. In the Eastern Shore county of Northampton, Virginia, the Northampton County Council recently voted to increase the minimum setbacks to 1,000 feet from a property line or public road, 1,500 feet from any existing subdivision or town edge district, and 2,000 feet from tidal waters. [2] These protective measures work to counter the growing problems with the industrialized CAFOs. CAFOs emit tons of ammonia and particulate matter from a single operation. Increasing the minimum setbacks in Maryland, county by county, is one strategy to prevent overdevelopment of CAFO operations in the state.   

Under Maryland Law, ammonia is a Class II Toxic Air Pollutant (TAP), which means it is a health hazard. [3] Because ammonia is a Class II TAP, operations emitting ammonia above certain levels must comply with regulations to limit adverse human health and environmental effects. [4] The Maryland Legislature has acknowledged the potential dangers posed by ammonia emissions in proposed amendments in the past. [5] Maryland’s placement of ammonia on the original Class II TAP list, coupled with its regulation of the pollutant, speaks to the state’s recognition of the numerous potential risks that ammonia poses.  These include numerous respiratory hazards for individuals working on or near animal confinement operations. Ammonia exposure can cause irritation to the eyes, skin, mucous membranes, and upper respiratory system. [6] Ammonia is water-soluble, and thus easily absorbed into the upper respiratory system. However, if high humidity and aerosols are present, the ammonia can absorb into the aerosols and be taken deeper into the lungs as particulate matter (PM2.5). [7] Ammonia is a precursor to PM2.5, meaning that gaseous ammonia has the potential to turn into particulate matter under certain conditions and pose an even greater risk to public health.  If PM2.5 is inhaled into the human body it may cause a variety of more serious respiratory diseases including bronchitis, asthma, and farmer’s lung. [8] Lingering ammonia produced by CAFOs over time creates clouds of particulate ammonia over communities that significantly threatens human health and exacerbates adverse health outcomes.  

In addition to the human health and environmental effects, CAFOs can also have a significant effect on property values. Living near a CAFO evokes fear of loss of amenities, perceived higher risk of water or air pollution, and the increased possibility of nuisances related to odors or insects. [9] CAFOs also decrease property values by creating stigma surrounding those who live near animal operations. [10] One study found that proximity to a hog CAFO decreased neighboring property values in the following order: 40% within ½ mile, 30% within 1 mile, 20% within 1.5 miles, and 10% within 2 miles.[11] One study determined that the largest negative effect on property value was found in properties downwind from CAFOs, suggesting that odor and emission of pollutants caused the decline.  At first glance, it seems that decreases in property value only affect the property owners themselves. However, the residential tax base may also suffer. [12]

In order to limit the adverse effects posed by CAFOs and the ammonia they emit, it is necessary to impose additional regulations on the CAFO industry. Municipalities like Wicomico County have sought to change the minimum setback requirements, while other citizen groups, including the Environmental Action Center, are advocating a regulatory change that would require all new CAFOs above a certain size to acquire a permit to operate from Maryland Department of the Environment. Still, because most concentrated animal feeding operations in Maryland have fewer than 250,000 birds, the new rule, if adopted, would only impact the largest operations that emit the majority of the ammonia into their local communities. [13] Regulating even this small fraction of industrial poultry CAFOs would tremendously improve the environmental, health, and social welfare of Maryland at little expense to the polluting industry. MDE must take these measures in order to protect the environment and the public it is charged with protecting.


[1] Greg Bassett, Hearing on poultry house zoning changes set Thursday, Salisbury Independent (June 5, 2016). Retrieved from: http://salisburyindependent.net/wicomico-news/hearing-poultry-zoning-changes-set-thursday-civic-center/

[2] Northampton County, Virginia Code of Ordinances Sec. 154.110 (F)(3).



[5] MD Fisc. Note, 2009 Sess. H.B. 395.

[6] National Library of Medicine, “Ammonia Poisoning,” Retrieved from: https://www.nlm.nih.gov/medlineplus/ency/article/002759.htm.  

[7] Dana Cole, Concentrated Swine Feeding Operations and Public Heath: A Review of Occupational and Community Health Effects, Environmental Health Perspectives, 685-86 (2000).

[8] Ammonia Best Practices, Colorado State University, (2008), Retrieved from: http://ammoniabmp.colostate.edu/link%20pages/impacts%20of%20ammonia.html#humanhealth.

[9]Carrie Hribar  & Mark Schultz, Understanding Concentrated Animal Feeding Operations and Their Impact on Communities, Centers for Disease Control and Prevention (2013) Retrieved from: https://www.cdc.gov/nceh/ehs/docs/understanding_cafos_nalboh.pdf

[10] John A. Kilpatrick, Final Report of a to Property Values by Chicken Operation in Colorado (2012), retrieved from http://www.sraproject.org/wp-content/uploads/2012/09/KilpatrickJardonMemoFinal1_Revised.pdf.

[11] William J. Weida, The CAFO: Implications for Rural Economies in the U.S. 1 (Colo. College & GRACE Factory Farm Project 2004).

[12] Doug Gurian-Sherman, Union of Concerned Scientists, CAFOs Uncovered: The Untold Costs of Confined Animal Feeding Operations 61 (April 2008).

[13] www.uspoultry.org/environment/docs/poultrypetition.pdf