A healthy agricultural industry and a healthy environment are both important to the nation. However, agricultural production can have varying impacts on the environment. The use of both natural resources (e.g., soil and water) and synthetic inputs (e.g., fertilizers and pesticides) in agricultural production can sometimes create a negative impact on the surrounding ecosystem. For example, soil erosion, farm chemical runoff, and overgrazing can affect water and air resources. Converting grassland prairies and wetlands to crop production can impact wildlife populations. The magnitude of these environmental impacts varies widely across the country and changes over time. Traditionally, farm and ranch operations have been exempt or excluded from many federal environmental statutes and regulations, and some point out that the relative number of environmental regulations affecting agriculture is small compared to other industries. Historically, environmental policies have focused on large industrial sources such as factories and power plants, because attempting to regulate numerous individual crop and livestock operations can be a challenge for government regulators. Therefore, the current federal farm policy addressing environmental concerns is in large part voluntary; that is, it seeks to encourage agricultural producers to adopt conservation practices through economic incentives. Because natural resources are a major input into most agricultural production, many in agriculture cite the health of the surrounding environment as being important for long-term productivity. However, given the agricultural sector's size in the landscape and its potential to affect its surrounding environment, there is interest in both managing potential impacts of agricultural actions on the environment and also maintaining an economically viable agricultural industry. The U.S. Environmental Protection Agency (EPA) is the primary federal authority for administering environmental protection policies, while the U.S. Department of Agriculture (USDA) is the primary federal authority for incentivizing agricultural production. Most environmental regulation, in terms of permitting, inspection, and enforcement, is done by state and local governments, typically based on policies administered by the EPA. USDA provides both educational outreach and technical and financial assistance opportunities for producers to implement environmentally sustainable practices. While many of these voluntary programs and policies have been in place for decades and have had considerable success, some question whether a strictly voluntary approach to agricultural conservation generates sufficient environmental gains. EPA, on the other hand, has recently received criticism from some lawmakers and industry leaders for appearing to focus some of its recent regulatory efforts on agriculture. Some claim EPA has overreached its regulatory authority. In general, agricultural industry groups, among others, have been vocal in their displeasure with recent EPA regulatory proposals and the costs associated with protecting public health and the environment. Others, such as environmental groups, have supported some of the regulatory actions and in some instances voiced concerns that the federal actions may not go far enough in protecting public health and the environment, prompting some lawmakers offer statements supporting various EPA regulatory efforts. Criticisms of the regulatory actions are reflected in recent legislative proposals that would restrict or prohibit certain actions. Beyond the criticism of individual regulations of EPA and other agencies, there also are calls for broad regulatory reforms, for example, to reinforce the role of economic considerations in agency decision making or to increase Congress's role in approving or disapproving regulatory decisions. Congress will likely continue to give attention to EPA's and other federal agencies' roles in regulating environmental protection. Both the Senate and House Committees on Agriculture have shown particular interest in EPA's actions and conducted oversight hearings on regulatory impacts on agriculture during the 112 th Congress. This report provides the background, status, and issues related to selected environmental regulations or initiatives possibly affecting agriculture that have drawn attention in and beyond Congress. An issue's inclusion in this report is not intended to suggest or imply that the regulation or action has either a beneficial or harmful effect on agriculture or to what degree. Similarly, regulatory actions not included in this report do not indicate the lack of potential impact on the agriculture sector. This report only addresses federal regulatory actions. In many cases, constraints on agricultural production to reduce pollution emissions arise at the state level in response to local concerns. State and local regulations are not specifically included in this report, but may be discussed generally where appropriate. Actions considered voluntary or in response to regulatory actions are also not included. This means that many USDA programs and initiatives, which offer funding to agricultural producers mitigate environmental impacts, are not discussed in this report. The majority of the regulations discussed in this report are administered by EPA, though not all. In some cases, agriculture is the direct or primary focus of the regulatory actions. In other cases, agriculture is one of many affected sectors. In many cases, for a regulation to become effective, EPA rules must be adopted by states to which the program has been delegated (e.g., most environmental permitting programs are delegated to qualified states). Moreover, many states require that the state legislature review new regulations before the new rules would take effect. The general regulatory development and compliance process can be tedious and complex. In some cases, the promulgation and implementation of regulations may take years. In the case of some environmental regulations, the agencies must adhere to court-ordered requirements and deadlines. This report has been revised and updated a number of times since its initial release in early 2011. A few of the initial issues covered in this report are no longer congressionally active, either due to enacted legislation or because of a change in Administration priorities. These issues have been removed and new emerging issues have been added. Congressional interest in environmental regulations affecting agriculture remains and oversight is ongoing. Legislative action and oversight is discussed within each of the sections below. The remainder of this report is organized under four broad subheadings: Air, Water, Energy, and Pesticides. Each section includes selected regulatory actions and provides background information and statutory authority, followed by the current status of the rule or regulatory action and issues identified or raised by the agricultural community regarding the regulatory action. Finally, each section identifies the appropriate CRS specialist for additional information; these contacts are also listed in Table 1 . Agricultural production practices from both livestock and crop operations generate a variety of substances that enter the atmosphere, potentially creating health and environmental issues. Agriculture's effect on air quality rose to national importance in the 1930s, when the conversion of native grasslands to cropland caused severe dust storms known as the Dust Bowl. The federal response to this phenomenon created many of the conservation outreach and education programs that remain in place today. While dust storms of this proportion are rare in the United States today, issues associated with soil erosion, particulates and farm chemical emissions, and livestock odor are still of concern. The following section covers five federal regulations relating to air, including mandatory reporting of greenhouse gases (GHGs); GHG emissions tailoring rule and the "cow tax"; reductions of emissions from gasoline/diesel powered stationary engines; national ambient air quality standards (particulate matter and ozone); and Emergency Planning and Community Right-to-Know Act (EPCRA) and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) reporting requirements. EPA was required by the FY2008 Consolidated Appropriations Act "to develop and publish a ... final rule not later than 18 months after the date of enactment of this Act, to require mandatory reporting of greenhouse gas (GHG) emissions above appropriate thresholds in all sectors of the economy of the United States." On October 30, 2009, EPA promulgated the final Greenhouse Gas Reporting Rule. The rule required suppliers of fossil fuels or industrial gases, manufacturers of vehicles and engines, owners or operators of electric power plants, and other—mostly industrial—sources to report their emissions of GHGs to EPA annually, beginning in 2011. Covered entities are required to report to EPA if they emit 25,000 tons or more of carbon dioxide or the equivalent amount of five other GHGs (methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride and other fluorinated gases). About 10,000 facilities in 31 categories of sources were covered by the rule, as promulgated. EPA subsequently added 11 other categories of sources. The only agricultural sources covered by the Reporting Rule are manure management systems that emit methane and nitrous oxide in amounts greater than the reporting threshold. EPA identified six specific categories of agricultural sources that could be subject to the rule: beef cattle feedlots; dairy cattle and milk production facilities; hog and pig farms; chicken egg production facilities; turkey production; and broilers and other meat type chicken production. In all, EPA estimates that 107 livestock facilities nationwide would need to report under the rule. In EPA's FY2010 appropriations act, however, Congress included language barring EPA from using funds under that act to implement mandatory GHG reporting by manure management facilities. This prohibition has been carried over into FY2011, FY2012, FY2013, and FY2014 by the continuing resolutions and appropriations acts that have funded EPA's continued operation, including P.L. 113-76 , the Consolidated Appropriations Act of 2014. Therefore, despite the inclusion of manure management systems among the regulated entities, no agricultural sources are currently required to comply with the Reporting Rule. For the facilities required to report, the rule imposes little cost because it only requires monitoring and reporting, and the monitoring does not require direct measurement of emissions. EPA considered requiring direct measurement of GHG emissions from manure management systems, but rejected the approach due to what it termed "the extreme expense and complexity of such a measurement program." Instead, the agency promulgated an approach that allows the use of default factors, such as a system emission factor, for certain elements of the calculation, combined with the use of site-specific data (e.g., number of livestock). EPA estimated the total annual cost of the rule for the 107 potentially affected manure management facilities at $300,000. In comments on the proposed rule, a number of agricultural stakeholders noted that agriculture as a whole is responsible for less than 1% of total GHGs emitted and questioned why manure management systems in particular were included in the proposal.