The Environmental Integrity Project (EIP) released a report in March 2011 analyzing Environmental Protection Agency (EPA) data on Confined Animal Feeding Operation (CAFO) emissions.

The two year air monitoring survey was jointly sponsored by the EPA and the livestock industry.  Results of the survey indicate that air quality near CAFOs may be unsafe for workers and residents in the area, as levels of particulate matter, ammonia, and hydrogen sulfide were found to be at levels well above federal standards.

EPA suspended enforcement of air quality laws against CAFOS five years ago for the duration of the study, and in 2008, EPA exempted CAFOs from most pollution requirements altogether.  However, based on the emissions reported by the study, many CAFOs release quantities of air pollutants that would trigger emission reporting laws in other large industries.

The stench of CAFOs is notorious–but these aren’t just unpleasant smells.  Both ammonia and hydrogen sulfide cause respiratory damage and can be deadly at high concentrations.  EPA has not set air quality standards for ammonia, but federal law requires ammonia sources to report emissions above 100 pounds per day.  Similarly, there are no EPA air quality standards for hydrogen sulfide, but federal right-to-know laws require reporting of emissions that exceed 100 pounds per day.

According to the EIP report, 11 of the 14 CAFOs studied emitted more than 100 pounds of ammonia on average days, which is higher than permitted by federal law for unreported emissions.  On the worst days, some emit thousands of pounds of ammonia.

In addition, workers were exposed to ammonia levels for entire work days that exceeded the National Institute for Occupational Safety and Health’s (NIOSH) recommended levels for 15-minute periods.  NIOSH recommends that workers be exposed to no more than 35 parts per million (ppm) of ammonia in any fifteen minute period, and it was shown in the data that ammonia concentrations in exhaust from swine barns and henhouses were much higher for entire days, sometimes reaching levels above 200 ppm.

NIOSH recommends limiting exposure to hydrogen sulfide to no more than 10 ppm for ten minutes at a time; average daily concentrations in one Iowa barn exceeded that amount for three days, and in the other barn for two, which suggests that workers may be exposed to higher-than-recommended concentrations of hydrogen sulfide.  Daily averaging of study data prevented EIP from isolating peak, short term exposures, so it is unknown if other monitoring sites exceeded recommended levels at certain points throughout the day.

Large hog and dairy CAFOs were found to release quantities of hydrogen sulfide comparable to those released by oil refineries, and fine particulate matter exceeded federal standards on the worst days for six of 15 study sites.

The EIP study recommends that EPA remove the exemption for CAFO emissions reporting, and that the Clean Air Act should also be used to protect the health of rural residents living near CAFOS.

For the full report, click here.