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Last week, a Maryland circuit court ruled that the state must regulate and limit ammonia pollution from industrial poultry operations. This landmark decision takes an important step toward protecting the environment and public health in the Old Line State and could spur similar action in other states.

It is certainly needed in Maryland. The state's Lower Eastern Shore is home to a large number of industrial poultry operations; three Lower Eastern Shore counties house close to 44 million chickens at any given time — roughly 241 times greater than the number of people in the region.

Every year, these operations release millions of pounds of ammonia — a form of nitrogen — into the environment, polluting our land, water, and air. Ammonia is a colorless compound formed when nitrogen in chicken manure breaks down. It enters the air as a gas and can land on the ground, polluting groundwater and nearby waterways.

Exposure to airborne ammonia contributes to poor health in nearby communities. Ammonia is water soluble and, when inhaled, quickly dissolves in the upper respiratory tract, irritating the eyes, nose, and throat. It also has a strong, unpleasant odor. In residential communities near industrial livestock operations, airborne ammonia concentrations are positively correlated with odor annoyance, which is defined as an odor that contributes to "a significant degradation in quality of life." Odor annoyances can also come from operations like sewage treatment plants, wasteyards, meat processing facilities, and chemical manufacturers.

While inhaling ammonia is associated with a host of public health problems, the focus of the court's opinion — and the crux of the case — is how ammonia pollution from large poultry operations impacts local waterways and the Chesapeake Bay.

In groundwater and surface waters, bacteria break ammonia down into nitrate and nitrite, two other forms of nitrogen. A 2020 CPR report found evidence of nitrate contamination in private wells sourced by groundwater, as well as public water utilities on the Lower Eastern Shore. Consuming high levels of nitrates in drinking water is associated with blue baby syndrome, a condition fatal to infants, certain types of cancer, pregnancy complications, and thyroid disease.

Environmental harms

Agriculture is responsible for more than 50 percent of Maryland's nitrogen load to the Chesapeake Bay, and its share is growing, hampering efforts to reduce pollution and restore clean water in the Bay and regional waterways. Excess nitrogen depletes the level of oxygen in water, creating "dead zones" that kill fish, other aquatic species, and underwater grasses and causing algal blooms, acidity spikes, and parasite growth.

While the agricultural industry continues to deny the connection between ammonia from industrial poultry operations and nitrogen pollution, last week's ruling recognizes that ammonia from these operations has a "definite and real impact on the Bay."

That's an important legal victory: Limiting ammonia pollution from these operations will reduce the agriculture sector's overall nitrogen load to the Bay and improve public and environmental health.

Importantly, the court found that the Maryland Department of the Environment can no longer ignore the impact of ammonia in its regulatory oversight role of industrial poultry operations. As a result, the department must revise the primary permit that regulates pollution from these operations so that it incorporates ammonia gas emissions limits.

This ruling, when implemented, means that industrial poultry operations in Maryland must finally monitor and account for their ammonia emissions. They will also likely have to utilize certain best management practices, such as the installation of trees, biofilters, and other vegetative buffers that can limit the dispersion of airborne ammonia.

The ruling also indirectly benefits nearby communities, which have long advocated for regulations on ammonia pollution to address poor air quality.

Nationwide, the impact of ammonia pollution from industrial agriculture operations on water quality has largely gone unchecked, much to the chagrin of environmental, public health, and community advocates who see and feel its firsthand impacts.

While last week's decision only affects Maryland, it could catalyze much-needed reform in other states, like Wisconsin and Iowa, where communities also suffer from ammonia pollution from industrial farms. Ammonia is harmful to waterways and people, regardless of where they are located — and poultry operations across the country should take notice that courts are cracking down on it.