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Controlling Emissions in Agriculture

Concentrated Animal Feed Operations (CAFOs)

Concentrated Animal Feeding Operation (CAFO) - Holstein Dairy Cows | Air Quality Emissions | Environment & Nature | Arkansas ExtensionThe ramifications of the Clean Air Act for agriculture continue to unfold with permits, penalties and enforcement under consideration.  The scientific data on livestock air emissions needed to properly regulate Concentrated Animal Feeding Operations (CAFOs) is limited.  EPA's Air Quality Compliance Agreement between EPA and the CAFO community was reached in 2005. The National Air Emission Monitoring Study (NAEMS), established in 2006 by a voluntary Air Compliance Agreement between EPA and the pork, dairy, egg and broiler industries, has been completed at selected livestock and poultry sites across the nation.

The purposes of this study were to:

  1. Accurately see emissions from livestock operations
  2. Compile a database for estimation of emission rates
  3. Promote a national consensus for emission-estimation methods/procedures

More than 2,000 CAFOs in the U.S. have signed agreements with the EPA regarding air compliance plans.  Air emissions from representative farms across the nation were monitored for two years on a 24/7 basis.  Data collection from all 14 CAFO barn sites was finished in 2010 and is currently under the review by the EPA.


Continuous Release Reporting Regulation

Animal waste is a source of ammonia and hydrogen sulfide releases to the air.  These are hazardous substances that, when released into the environment above certain quantities, trigger notification responsibilities under federal regulations.  The reportable quantity for ammonia and hydrogen sulfide is 100 pounds within any 24-hour period.  The following air regulations affect CAFOS and their reporting of hazardous substances:

  • The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)

  • The Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA)

These regulations require facility owners or operators to notify all authorities when a reportable quantity of hazardous substance (e.g. hydrogen sulfide, ammonia) is released. This allows citizens and authorities to know the sources and amount of hazardous materials being released into their local environment.

A rule finalized by EPA in December 2008 provided a full exemption for reporting air releases of hazardous substances from animal waste at livestock farms to the federal government and a partial exemption of reporting the air releases to state and local governments.  This rule exempts all farms from reporting releases to any federal governments under CERCLA. The requirements for CAFOs to report certain types of releases to local and state agencies, as directed by EPCRA remain unchanged.

Poultry Farm Fans | Air Quality Emissions | Environment & Nature | Arkansas ExtensionReporting Deadlines

January 20, 2009 was the date by which the above mentioned exemptions became effective.  Prior to January 20, 2009, all operations were required to report to both EPCRA and CERCLA. The change in this regulation is that as of January 20, 2009 no animal feeding operations are required to report to CERCLA and only large CAFOs are required to report to EPCRA. The large CAFOs have always been required to report to EPCRA although most have not done so.  Therefore, there is no change in this requirement.  It should be noted that if large CAFOs are concerned about their liability to report to EPCRA they can begin reporting at any time.

How to Report?

The decision to report under EPCRA regulations is at the discretion of the producer and the producer should approach the decision thoughtfully and by using the best possible tools available to determine if their operation meets the reporting requirements.

It should be noted that after a producer has contacted the State Emergency Response Commission (SERC) and the Local Emergency Planning Commission (LEPC), a written report needs to be filed within 30 day of the original call to SERC and LEPC.

Under the continuous release reporting regulation, no further reporting is required for routine air releases unless the rate, quantity, or ownership changes. If a producer signed up for the air quality consent agreement back in 2008, no action is required at this time. Producers who are unsure about their participation in the CAFO air quality consent agreement may contact Tim Sullivan at EPA Headquarters 202.564.2723 to determine if they are involved in that agreement.

Ammonia and Hydrogen Sulfide Emission Rates for Poultry Operations 
Hongwei Xin, Robert Burns, and Hong Li | Agricultural and Biosystems Engineering Dept. |  Iowa State University

Thresholds for large CAFO designation

RICE:  Reciprocating Internal Combustion Engine

Irrigation power unit | Reciprocating Internal Combustion Engine | Air Quality Emissions | Environment & Nature | Arkansas ExtensionReciprocating Internal Combustion Engines (RICE) are commonly used to power pumps (e.g. crop irrigation stations) and compressors.  They are also used in emergencies to produce electricity (e.g. commercial poultry farms) and pump water for flood and fire control.  As of January 2013 (effective April 2013) the EPA finalized new regulations that place requirements on owners and operators of RICE equipment

Why does EPA Regulate RICE?

RICE are combustion sources that emit air toxins include formaldehyde, acrolein, acetaldehyde and methanol.  Exposure to these air toxins may produce health symptoms including irritation of the eyes, skin and mucous membranes, and central nervous system problems.  RICE engines also emit the conventional air pollutants created when fuel is burned such as carbon monoxide, nitrogen oxides, VOCs and particulate matter.

How does EPA Regulate RICE?

Emergency generator | Air Quality Emissions | Environment & Nature | Arkansas Extension

The National Emission Standards for Hazardous Air Pollutants (NESHAP) for RICE has several subparts with rules based on specific criteria:

  • new engine (manufactured after 2006) or existing

Existing Farm Engine Emission - Standards

Existing Farm Engine Emission - Compliance Requirement

  • area source or a major source (annual  emissions quantity)

Area Source versus Major Source

  • compression ignition (CI) or a spark ignition (SI)

The only engines not subject to NESHAP for RICE are the existing emergency engines located at residential, institutional, or commercial area sources which are obligated to be available ≤ 15 hr/yr for emergency demand response.

NESHAP for RICE acronyms and definitions

Stationary Engine Subcategories

Emergency Engine definition (owned by most poultry farms)

Stationary Internal Combustion Engines - US EPA

Historical RICE rule and recent amendments - US EPA

Additional Resources for Air Emissions

Compilation of Air Pollutant Emission Factors (AP 42) | Chapter 9 - Food and Agricultural Industries - US EPA

Airborne Emissions in Animal Agriculture - Air Quality Education in Animal Agriculture (AQEAA) at

Concentrated Animal Feeding Operations (CAFOs) - US EPA Region 6