In letters to 10 public interest, environmental, and animal welfare groups, EPA Administrator Scott Pruitt said the Agency was denying the groups’ 2009 petition to develop New Source Performance Standards (NSPS) for concentrated animal feeding operations (CAFOs) as well as regulations for state performance standards for existing CAFOs.
The main reason for the denial, according to Pruitt, is the current unavailability of methods to accurately estimate emissions of pollutants from the many different types of CAFOs. These emissions can be highly variable because of the inconsistency among CAFOs that house different animal species and other complicating factors, such as wind and weather patterns, animal feeds used, soils, and types of confinement structures, the letter stated.
The letter included two additional reasons for the denial. One is the ongoing National Air Emissions Monitoring Study (NAEMS), which is intended to but has not yet formally identified methodologies to estimate emissions of ammonia, hydrogen sulfide, particulate matter (PM), and volatile organic compounds (VOCs) from a wide variety CAFOs. Second, at present, the Agency has higher priorities for its shrinking staff and generally declining budget.
None of this, Pruitt adds, is intended to suggest that the EPA will not in the future decide that CAFOs should be subject to the same types emissions limits imposed on traditional stationary sources under the Clean Air Act (CAA).
CAA Section 111
The petitioners requested that the EPA exercise its authority under CAA Section 111 to list and “from time to time” revise the list of stationary source categories that significantly contribute to air pollution that may endanger public health or welfare. Also, within 1 year of a sector’s addition to the list, the section requires that the Agency propose standards of performance for new sources within that sector and, then, 1 year after publishing the proposal, promulgate final standards.
Section 111 also requires the EPA to determine the best system of emission reduction (BSER) for the listed source category and determine what degree of emission reduction is achievable from the application of that BSER to sources in the source category.
“This limited timeframe [sic] for proposal and promulgation of standards necessitates that EPA gather sufficient and sufficiently reliable information to facilitate consideration of control options and the development of BSER prior to listing a new source category; otherwise, it would be difficult for the EPA to meet these statutory deadlines,” says Pruitt.
Methodologies
The letter asserts that CAFO emissions cannot be standardized based solely on the number and type of animals at each operation. For example, says Pruitt, there are many scenarios when a CAFO with fewer animals will have higher emissions than a CAFO with a greater number of the same species of animals.
“Further, historic emission-measurement techniques, such as those used in some of the studies cited by the petitioners, vary widely, and many are imprecise and impacted by local conditions,” the letter adds. “This variability makes it difficult to compare or aggregate results of multiple studies for the purposes of developing simple emission-estimating methodologies. Therefore, historic studies on CAFO emissions provide insufficient information to accurately characterize the nature and extent of the emissions, which is necessary information not only for evaluating regulatory options, but also for reaching the conclusions needed to list a source category under CAA section 111 if the EPA ultimately decides to do so.”
With improved emissions inventories that result from the use of reliable emissions estimation methodologies, Pruitt says the EPA then can best evaluate the impacts of CAFO air emissions on public health and welfare and implement a comprehensive regulatory strategy under the CAA to best address those emissions from the animal feeding sector.
Other actions
Pruitt notes that other CAA programs—e.g., the National Ambient Air Quality Standards (NAAQS) and the National Emissions Standards for Hazardous Air Pollutants (NESHAP)—in addition to Section 111 authorities may also be appropriate for regulation of the sector.
In addition, Pruitt points out that in September 2017, the EPA and the Department of Agriculture released a best management practices document for livestock and poultry production farms, including CAFOs (Agricultural Air Quality Conservation Measures: Reference Guide for Poultry and Livestock Production Systems).
“This document identifies measures that have been demonstrated to reduce air emissions of pollutants (ammonia, greenhouse gases, hydrogen sulfide, PM and VOC) from farms, states the letter. “While it does not involve the quantification of emissions, the guide clearly describes different practices and control technologies that reduce emissions of these pollutants.”
Pruitt’s letter is at https://www.regulations.gov, docket EPA–HQ–OAR–2017–0638.