Introduction Over the past couple of decades, national attention to "emerging contaminants" or "contaminants of emerging concern" (CECs) in surface water and groundwater has been increasing. Although there is no federal statutor y or regulatory definition of CECs, generally, the term refers to unregulated substances detected in the environment that may present a risk to human health, aquatic life, or the environment. CECs can include many different types of manmade chemicals and substancesâsuch as those in personal care products, pharmaceuticals, industrial chemicals, lawn care and agricultural products, and microplasticsâas well as naturally occurring substances such as algal toxins or manganese. CECs often enter the environment, including ground and surface waters, via municipal and industrial wastewater discharges and urban and agricultural storm runoff. Although municipal and industrial wastewater are both treated prior to discharge into waterways, treatment facilities are often not designed to remove CECs. The availability of data on CECsâsuch as concentration and pervasiveness in the environment or exposure or toxicity data that would help determine their risk to humans and aquatic lifeâmay be limited. In some cases, detections of CECs in the environment have triggered a call for action from federal, state, and local government, as well as Congress. Increased monitoring and detections of one particular group of chemicals, per- and polyfluoroalkyl substances (PFAS), has recently heightened public and congressional interest in these CECs and has also prompted a broader discussion about how CECs are identified, detected, and regulated and whether additional actions should be taken to protect human health and the environment. Several statutesâincluding the Safe Drinking Water Act; the Toxic Substances Control Act (TSCA); the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA); and the Clean Water Act (CWA) âprovide authorities to the U.S. Environmental Protection Agency (EPA) and states to address particular CECs. In the 116 th Congress, Members have introduced more than 40 bills to address PFAS through various means. Multiple bills, including House- and Senate-passed National Defense Authorization Act (NDAA) bills for FY2020 ( H.R. 2500 and S. 1790 , respectively), would direct EPA to take regulatory and other actions to address PFAS under several environmental statutes. Two of these bills ( H.R. 2500 and H.R. 3616 ) would direct EPA to address PFAS using authorities provided to the agency under the CWA, which Congress established to restore and protect the quality of the nation's surface waters. Global concern about another group of CECsâmicroplasticsâand their potential impacts has also been mounting. Recent studies have found that treated effluents from wastewater treatment plants can be key sources of microplastics, as can runoff from agricultural sites where sewage sludge from the wastewater treatment process has been applied as fertilizer. As with many other CECs, wastewater treatment facilities are generally not designed to screen for microplastic debris, such as microbeads, plastic fragments, or plastic fibers from clothing. Congress has shown interest in addressing the impacts of plastic pollution. In 2015, Congress passed legislation to ban plastic microbeads from rinse-off personal care products ("Microbead-Free Waters Act of 2015," P.L. 114-114 ). More recently, some Members in the 116 th Congress announced plans to introduce comprehensive legislation to address plastic waste in fall 2019. Some stakeholders have asserted that EPA could be more effective in using its existing CWA authorities to address CECs, while others have suggested a need to identify and address potential gaps in CWA authorities through amendments to the statute. This report examines authorities available to address CECs under the CWA. Addressing CECs through the Clean Water Act EPA has several CWA authorities it may use to address CECs, although it faces some challenges in doing so. The CWA's stated objective is "to restore and maintain the chemical, physical, and biological integrity of the Nation's waters." To help achieve this objective, the CWA prohibits the discharge of pollutants from any point source (i.e., a discrete conveyance, such as a pipe, ditch, etc.) to waters of the United States without a permit. Under the CWA, one of the primary mechanisms to protect or improve surface water quality is to limit or prohibit discharges of contaminants, including CECs, in National Pollutant Discharge Elimination System (NPDES) permits. The CWA authorizes EPA and delegated states to set limits or prohibit discharges of pollutants in permits through technology-based effluent (i.e., discharge) limitations and standards and through water-quality-based effluent limitations, which are established through water quality standards and criteria. Technology-based effluent limitations are specific numerical limits (i.e., maximum allowable levels of specific pollutants) that represent the minimum level of control that must be established in a permit. In cases where technology-based effluent limitations are not adequate to meet applicable water quality standards, the permits also incorporate water-quality-based effluent limitations. Water-quality-based effluent limitations are specific limits established in a permit that, if not exceeded in the discharge, allow for attainment of water quality standards in the receiving water. Water quality standardsâestablished by states, territories, tribes, and EPAâdefine the desired condition or level of protection of a water body and what is needed to achieve or protect that condition. In addition, the CWA authorizes EPA to designate contaminants as toxic pollutants (CWA Â§307) or as hazardous substances (CWA Â§311), which may trigger other actions under the CWA and CERCLA. This section first identifies the authorities available under the CWA, their applicability to CECs, and potential challenges with EPA use of these authorities. Technology-Based Requirements The CWA requires EPA to establish technology-based effluent limitations for various categories of point sources/dischargers . Technology-based requirements consider the performance of specific technologies as well as economic achievability. These limits do not specify what technologies must be employed; rather , they establish the levels of specific pollutants that are allowable in the discharge based on the performance of technologies identified as representing specified levels of control (e.g., best available technology economically achievable, best conventional pollutant control technology). CWA Section 301 prescribes the levels of control required. EPA broadly classifies NPDES permittees as either (1) publicly owned treatment works (POTWs) or (2) non-POTWs, which include all other point sources and are also often called n on municipal facilities or industrial facilities . The CWA requires POTWs to meet secondary treatment standards as determined by EPA. Secondary standards are based on performance data for POTWs that use physical and biological treatment to remove or control conventional pollutants. As shown in Figure 1 , the CWA requires non-POTW dischargers to achieve specified levels of control based on (1) whether a discharger directly or indirectly discharges into a water of the United States (an indirect discharger discharges to a POTW for treatment prior to discharge into a water of the United States), (2) whether the discharger is a new or existing source, and (3) the category of pollutant (conventional, toxic, or nonconventional ). Effluent Limitation Guidelines and Standards (ELGs) The CWA requires EPA to publish national regulations for non-POTW dischargersâcalled Effluent Limitation Guidelines and Standards (ELGs)âwhich set minimum standards for specific pollutants in industrial wastewater discharges based on the specified levels of control. Since 1972, EPA has developed ELGs for 59 industrial categories. For direct dischargers, states or EPA incorporate the limits established in ELGs into the NPDES permits they issue. For indirect dischargers, pretreatment standards established in ELGs to prevent pass through and interference at the POTW apply. The CWA requires EPA to annually review all existing ELGs to determine whether revisions are appropriate. In addition, CWA Section 304(m) requires EPA to publish a plan every two years that includes a schedule for review and revision of promulgated ELGs, identifies categories of sources discharging toxic or nonconventional pollutants that do not have ELGs, and establishes a schedule for promulgating ELGs for any newly identified categories. In its 2002 draft Strategy for National Clean Water Industrial Regulations , EPA described a process for identifying existing ELGs that the agency should consider revising as well as industrial categories that may warrant development of new ELGs. As outlined in the strategy, EPA considers four main factors when prioritizing existing ELGs for possible revision: (1) the amount and type of pollutants in an industrial category's discharge and the relative hazard to human health or the environment, (2) the availability of an applicable and demonstrated wastewater treatment technology, process change, or pollution prevention measure that can reduce pollutants in the discharge and the associated risk to human health or the environment; (3) the cost, performance, and affordability or economic achievability of the wastewater treatment technology, process change, or pollution prevention measure; and (4) the opportunity to eliminate inefficiencies or impediments to pollution prevention or technological innovation or promote innovative approaches. EPA considers nearly identical factors in deciding whether to develop new ELGs. EPA uses a variety of screening-level analyses to address these factors. These analyses evaluate discharge monitoring reports and EPA's Toxic Release Inventory to rank industrial categories according to the total toxicity of their wastewater. In 2012, the Government Accountability Office recommended that the annual review include additional industrial hazard data sources to augment its screening-level reviews. In response, EPA has begun to use additional data sources that provide information about CECs or new pollutant discharges, industrial process changes, and new and more sensitive analytical methods, among other things. For example, EPA has reviewed data from the agency's Office of Pollution Prevention and Toxics to identify potential CECs. If EPA identifies an industrial discharge category warranting further review, it conducts a more detailed review, which may lead to a new or revised guideline. EPA published its most recent effluent guidelines program planâthe Final 2016 Effluent Guidelines Program Plan âin April 2018. It identified one new rulemaking to revise the Steam Electric Power Generating Point Source Category ELG but concluded that no other industries warrant new ELGs at this time. In its plan, EPA also announced that it is initiating three new studies: a holistic look at the management of oil and gas extraction wastewater from onshore facilities, an industry-wide study of nutrients, and an industry-wide study of PFAS. Options to Address CECs through Technology-Based Requirements Both EPA and states have authority under the CWA to address CECs through technology-based effluent limitations using ELGs or by setting technology-based effluent limits in NPDES permits on a case-by-case basis. In addition, the CWA authorizes EPA to add contaminants to the Toxic Pollutant List. ELGs When EPA develops an ELG for a new industrial category or revises an existing ELG, it is for the industrial categoryânot a specific pollutant. However, as evidenced in the agency's most recent effluent guidelines program plan, EPA may initiate a cross-industry review of particular pollutants (such as the agency is doing with PFAS and nutrients). EPA uses such reviews to prioritize further study of the industrial categories that may be candidates for ELG development or revision to control the discharges of those particular pollutants. If EPA were to determine that new or revised ELGs are warranted to control discharges of those pollutants, and the agency had the necessary data to support the development or revision, the agency could initiate a rulemaking process to do so. Establishing Technology-Based Effluent Limits in NPDES Permits on a Case-by-Case Basis The CWA also authorizes EPA and states to impose technology-based effluent limits in NPDES permits on a case-by-case basis when "EPA-promulgated effluent limitations are inapplicable." This includes when EPA has not developed ELGs for the industry or type of facility being permitted or pollutants or processes are present that were not considered when the ELG was developed. This provides a means for the permitting authority to restrict pollutants in a facility's discharge even when an ELG is not available. CWA regulations require best professional judgment to set case-by-case technology-based effluent limits, applying criteria that are similar to the analysis EPA uses to develop ELGs but are performed by the permit writer for a single facility. Toxic Pollutant List The CWA also authorizes EPA to designate contaminants as toxic pollutants, which can trigger other actions under the CWA and CERCLA. (For a discussion of the effect of designating a contaminant as a toxic pollutant on the treatment of that contaminant under CERCLA, see " Designating CECs as Toxic Pollutants or Hazardous Substances .") CWA Section 307 authorizes EPA to designate toxic pollutants and promulgate ELGs that establish requirements for those toxic pollutants. Section 307(a)(1) directed EPA to publish a specified list of individual toxic pollutants or combination of pollutants and, from time to time, add or remove any pollutant that possesses certain properties. EPA adopted the initial list of 65 toxic pollutants in 1978, as directed by Congress. Since that time, the list of 65 toxic pollutants has generally not changed. Section 307(a)(1) directs EPA to "take into account the toxicity of the pollutant, its persistence, degradability, the usual or potential presence of the affected organisms in any waters, the importance of the affected organisms, and the nature and extent of the effect of the toxic pollutant on such organisms" when revising the Toxic Pollutant List. Section 307(a)(2) authorizes EPA to develop effluent limitations for any pollutant on the Toxic Pollutant List based on best available technology. Notably, however, EPA has the authority to develop effluent limitations for any pollutant regardless of whether it is on the Toxic Pollutant List. Adding a pollutant to the Toxic Pollutant List would trigger an additional requirement for states. Section 303(c)(2)(B) of the CWA requires states, whenever reviewing, revising, or adopting water quality standards, to adopt numeric criteria for all toxic pollutants listed pursuant to Section 307, for which EPA has published water quality criteria under Section 304(a). EPA and states use both the ELGs for industrial categories and state water quality standards in establishing pollutant limits in permits under Section 402. (See Figure 1 .) Challenges to Addressing CECs through Technology-Based Requirements EPA and states face a number of challenges in addressing CECs through technology-based effluent limitations. In particular, EPA officials stated that in developing a new ELG or updating an existing ELG, the agency needs to gather extensive supporting information. This effort includes identifying the pollutants of concern; evaluating the levels, prevalence, and sources of those pollutants of concern; determining whether the pollutants are in treatable quantities and whether effective treatment technologies are available; and developing economic data to project the cost of treatment, among other things. Also, EPA and state officials have asserted that it is difficult for the agency and its CWA programs to keep pace with the growth of new chemicals in commerce. Accordingly, the agency is generally reactive rather than proactive in addressing CECs. EPA officials stated that identifying demonstrated treatment technologies and documenting their efficiency is especially challenging. The officials further stated that the most difficult task is showing that any technology selected as the basis for an ELG is economically achievable for the industry. In addition, EPA and states often lack analytical methods to measure an emerging contaminant. Even where analytical methods are available, there is still often a lack of data on the levels of the contaminant in dischargers' effluent and/or in the receiving surface waters. The two sources of data most readily available to EPAâdischarge monitoring report data and toxic release inventory dataâare limited to specific contaminants on which industry is required to report. EPA stated that the agency's capacity to collect dataâincluding obtaining clearance to request and collect the data and undertaking the extensive effort to do soâis limited in light of their staffing levels and resources. Should EPA have enough data to determine that a new or revised ELG is warranted and announce its intent to do so in an effluent guidelines program plan, the time it takes to issue the regulation varies, according to EPA officials. CWA Section 304(m) establishes a three-year time limit for new ELGs. For revised ELGs, the EPA officials stated that the time can vary depending upon the availability of data and the level of complexityâsome may be very technical and involve many wastestreams. Two of the more recently issued ELGsârevisions of the oil and gas extraction and steam electric power generating categoriesâtook five and six years, respectively. Water-Quality-Based Requirements Under the CWA, water quality standards translate the goals of the act (e.g., fishable and swimmable waters, no toxic pollutants in toxic amounts) into measurable objectives to protect or improve water quality. States, territories, and authorized tribes (hereinafter referred to collectively as states) are required to adopt water quality standards for waters of the United States, subject to EPA approval. They may also adopt standards for additional surface waters if their own state laws allow them to do so. Water quality standards consist of three key required components: 1. Designated uses for each water bodyâfor example, recreation (swimming or boating), aquatic life support, fish consumption, public water supply, agriculture; 2. Criteria , which describe the conditions in a water body necessary to support the designated usesâexpressed as concentrations of pollutants or other quantitative measures or narrative statements; and 3. An antidegradation policy for maintaining existing water quality. States have the primary authority to adopt, review, and revise their water quality standards and implementation procedures. The CWA requires states to review their water quality standards at least once every three years. EPA is required to review the states' water quality standards. Water Quality Criteria Water quality criteria prescribe limits on specific contaminants or conditions in a water body that protect particular designated uses of the water body. Both the EPA and states have roles in establishing water quality criteria under CWA Section 304(a) and 303(c)(2), respectively. EPA Role CWA Section 304(a) requires EPA to develop and publish and "from time to time thereafter revise" criteria for water quality that accurately reflect the latest scientific knowledge. These criteria are recommendations to states for use in developing their own water quality standards. EPA has developed several different types of criteria, including human health criteria, aquatic life criteria, and recreational criteria. EPA has also published guidelines for deriving water quality criteria, which the agency uses to develop new criteria under Section 304(a). These guidelines also serve as guidance to states as they adjust water quality criteria developed under Section 304(a) to reflect local conditions or develop their own scientifically defensible water quality criteria. EPA most recently updated its human health criteria in 2015, revising 94 of the 122 existing human health criteria. EPA last updated its methodology for deriving human health criteria in 2000, incorporating "significant scientific advances in key areas such as cancer and non-cancer risk assessments, exposure assessments, and bioaccumulation in fish." EPA's national recommended aquatic life criteria table currently includes 58 criteria. Many of these criteria were published prior to 1990. In the past 10 years, EPA has published two new criteria. EPA has not updated its guidelines for deriving aquatic life criteria since 1985. According to EPA, however, the guidelines allow for best professional judgment, which they have used in more recent criteria development and updates. The agency recognizes that since 1985, there has been substantial scientific advancement that warrants updating these guidelines. EPA formally initiated the guidelines revision process in 2015. However, according to EPA officials, the agency has shifted its focus from updating the guidelines to determining whether available data and research support development of human health criteria for PFAS. In doing so, EPA officials indicated they plan to use information gathered for the guidelines revision and also noted that they are not tied to the 1985 guidelines due to the best professional judgment clause included therein. EPA's recreational water quality criteria are national recommendations for all inland and coastal waters that have a primary contact recreation (i.e., swimming) designated use. EPA establishes recreational water quality criteria to help protect against illness caused by organismsâsuch as viruses, bacteria, and their associated toxinsâin water bodies. In 2012, EPA updated its recreational water quality criteria, which it had last issued in 1986. Additionally, in June 2019, EPA published final recreational water quality criteria for two algal toxins, which are commonly present in harmful algal blooms, to supplement the 2012 recreational water quality criteria. In addition, EPA is currently developing recreational water quality criteria for coliphage, a viral indicator of fecal contamination. State Role States use EPA's criteria as guidance in developing their own water quality standards. CWA Section 303(c)(2) requires states to adopt criteria to protect the designated uses of their water bodies and to also adopt criteria for all toxic pollutants listed pursuant to Section 307(a)(1), for which EPA has published criteria under Section 304(a). States' water quality criteria must be based on sound scientific rationale, contain sufficient parameters or constituents to protect the designated uses, and support the most sensitive use for water bodies with multiple designated uses. EPA regulations further require that states should establish numeric criteria based on CWA Section 304(a) guidance, CWA Section 304(a) guidance modified to reflect site-specific conditions, or other scientifically defensible methods. Where numeric criteria cannot be established, states are required to establish narrative criteria or criteria based on biomonitoring methods. States may adopt more stringent criteria than what EPA recommends, including for pollutants or parameters for which EPA has not promulgated 304(a) criteria. Options to Address CECs through Water-Quality-Based Requirements EPA and states may establish water quality criteria for CECs. If EPA were to establish criteria under CWA Section 304(a) for a CEC, that action alone would not necessarily require states to adopt criteria for that contaminant. As explained above, the CWA requires that states adopt criteria to protect their designated uses into their water quality standards. EPA's regulations provide that if a state does not adopt new or revised criteria for parameters for which EPA has published new or updated recommendations, then the state shall provide an explanation. States are explicitly required, as explained above, to adopt criteria for a contaminant if EPA designates it as a toxic pollutant under CWA Section 307 and publishes criteria for that contaminant under Section 304(a). Once a state has adopted water quality criteria for a contaminant as part of its state water quality standards and those standards have been approved, several CWA tools are available for achieving those standards. The primary tool is to limit or prohibit discharges of the contaminant in NPDES permits. In some cases, the technology-based effluent limits may already enable attainment of state water quality standards. In instances where they do not, the permit writer is required to establish water-quality-based effluent limitations. If a water body is not attaining its designated use (i.e., is "impaired" for that use), the Total Maximum Daily Load (TMDL) may also be used. A TMDL, essentially a "pollution diet" for a water body, is the maximum amount of a pollutant that a water body can receive and still meet water quality standards and an allocation of that amount to the pollutant's sources (including a margin of safety). TMDLs consider point sources, which can be addressed through permits, as well as nonpoint (diffuse) sources, which are more often addressed through best management practices and related efforts under CWA Section 319 nonpoint source management programs. Challenges to Addressing CECs through Water-Quality-Based Requirements A key challenge is often a lack of data about the occurrence, concentration, and persistence of CECs in the environment, as well as the effects on human health and aquatic life. Detection of a contaminant does not necessarily trigger regulatory measures. Information on the potential for the contaminant to adversely affect human health and aquatic life, potential exposure pathways, and other data would also be needed to inform such decisions. Developing new water quality criteria or updating existing criteria can often be time intensive, particularly in cases where data are limited. The general process for developing criteria involves a number of steps, including problem formulation and developing an analysis plan; gathering data and analyzing relevant studies; drafting the criteria document; a rigorous review process (e.g., branch level, office level, interagency, and independent external peer review); public notice and comment, and revising and publishing the criteria. According to EPA officials, the time it takes to develop or update criteria is often a function of the data that are available. EPA officials noted that developing criteria can take several years or longer. For example, the 2016 update for the aquatic life water quality criteria for seleniumâan effort characterized by EPA as complicated, in part because of the contaminant's bioaccumulative propertiesâtook 10 years to complete. In other cases, such as when a contaminant has an existing EPA Integrated Risk Information System value, developing or updating the human health water quality criteria for that contaminant may take less time, according to EPA officials. In May 2019, a report from the Contaminants of Emerging Concern Workgroup, convened by the Association of State Drinking Water Administrators and the Association of Clean Water Administrators, provided recommendations from state regulators regarding the ways state and federal agencies could improve the management of CECs. The report stated the following: The use of existing authorities and processes under the CWA and [Safe Drinking Water Act] to establish new criteria or standards is onerous, can take decades to implement, and does not meet public expectations for timely identification and prioritization of CECsâ¦. However slow these federal processes are, many state agencies do not have the infrastructure (i.e., sufficient funds and/or staffing levels), regulatory authority, or technical expertise to derive their own criteria or set their own standards for drinking water, surface water, groundwater, and fish tissue. Among numerous other recommendations provided in the report, the CEC workgroup recommended that EPA work with states to generate a list of priority CECs. To that end, EPA officials stated that they are developing a more formalized prioritization process for determining which contaminants warrant criteria development that will incorporate input from multiple stakeholders (including states), leverage information collected under the Safe Drinking Water Act, and incorporate monitoring and other data (e.g., ambient water concentrations). Designating CECs as Toxic Pollutants or Hazardous Substances Two sections of the CWAâSections 307 and 311âauthorize EPA to designate contaminants as toxic pollutants and hazardous substances, respectively. Designating a contaminant under Section 307 or Section 311 of the CWA has implications for how the contaminant is treated under CERCLA. CERCLA defines the term hazardous substance to include toxic pollutants designated under CWA Section 307 and hazardous substances designated under CWA Section 311 (as well as substances designated under certain other statutes and other chemicals that EPA may designate as hazardous substances). Toxic PollutantsâCWA Section 307 EPA's authority to designate contaminants under CWA Section 307 as toxic pollutants and the CWA-related implications of that designation are discussed above under " Toxic Pollutant List ." Hazardous SubstancesâCWA Section 311 CWA Section 311(b)(2)(A) authorizes EPA to promulgate a rule designating as a "hazardous substance" any element or compound that, when discharged as specified under the section, would present an imminent and substantial danger to public health or welfare, including but not limited to fish, shellfish, wildlife, shorelines, and beaches. EPA is authorized to revise the list of hazardous substances subject to these criteria as may be appropriate. EPA finalized the initial list of hazardous substances in 1978 and thereafter revised the list in 1979, 1989, and 2011. Pursuant to Section 311(b)(4), EPA established "harmful" quantities for these substances that are subject to the reporting of discharges prohibited under Section 311(b)(3). Section 311(b)(5) requires a person in charge of a vessel or facility to notify the National Response Center, administered by the U.S. Coast Guard, as soon as that person has knowledge of a discharge. Discharges permitted under other provisions of the CWA or otherwise allowable under certain other federal, state, and local regulations are excluded from reporting under CWA Section 311. CWA Section 311(c) authorizes federal actions to remove a prohibited discharge of a hazardous substance (or oil). CWA Section 311(f) establishes liability for the recovery of removal costs, including restoration of damaged natural resources. Section 311(e) authorizes enforcement orders to require a responsible party to abate an imminent and substantial threat to public health or welfare from a prohibited discharge, or threat of a harmful discharge, of a hazardous substance (or oil). Implications of CWA Designations on CERCLA If EPA were to designate a CEC, or any contaminant, as a toxic pollutant or hazardous substance under the CWA, that contaminant would, by statutory definition, be defined as a hazardous substance under CERCLA. CERCLA authorizes federal actions to respond to a release, or substantial threat of a release, of a hazardous substance into the environment in coordination with the states. CERCLA similarly authorizes response actions for releases of other pollutants or contaminants that may present an imminent and substantial danger to public health or welfare. CERCLA also establishes liability for response costs and natural resource damages but only for hazardous substances and not for other pollutants or contaminants. CERCLA response authority is available for releases of pollutants or contaminants but without liability to require a potentially responsible party to perform or pay for response actions. Designating a CEC as a toxic pollutant or hazardous substance under the CWA would have the effect of establishing liability for their release as a hazardous substance under CERCLA. However, releases in compliance with a CWA permit would be exempt from liability under CERCLA as a "federally permitted release" based on the premise that the permit requirements would mitigate potential risks. CWA Section 311 also establishes liability for releases of hazardous substances, but CERCLA liability and enforcement mechanisms are broader than the CWA. In practice, CERCLA has been the principal federal authority used to respond to discharges of hazardous substances into surface waters and to enforce liability, although the enforcement authorities of CWA Section 311 remain available to EPA. For a broader discussion of CERCLA, see CRS Report R41039, Comprehensive Environmental Response, Compensation, and Liability Act: A Summary of Superfund Cleanup Authorities and Related Provisions of the Act , by David M. Bearden. Legislation in the 116th Congress Recent congressional interest in CECs has largely focused on addressing one particular group of CECsâPFASâand addressing them through several statutes, such as the Safe Drinking Water Act. However, legislation in the 116 th Congress proposes to address PFAS using CWA authorities. H.R. 3616 âthe Clean Water Standards for PFAS Act of 2019âand Section 330A of H.R. 2500 , the House-passed version of the NDAA for FY2020, would direct EPA to add PFAS to the CWA Toxic Pollutant List and publish ELGs and pretreatment standards for PFAS within specified time frames. In addition, Section 330G of the House-passed version of the NDAA bill, Sections 6731-6736 of S. 1790 (the Senate NDAA bill), H.R. 1976 , and S. 950 would direct the U.S. Geological Survey (USGS) to carry out nationwide samplingâin consultation with states and EPAâto determine the concentration of perfluorinated compounds in surface water, groundwater, and soil. These bills would also require USGS to prepare a report for Congress and provide the sampling data to the EPA as well as other federal and state regulatory agencies that request it. Additionally, the bills would require the data to be used to "inform and enhance assessments of exposure, likely health and environmental impacts, and remediation priorities." Some Members have also introduced legislation to require comprehensive PFAS toxicity testing ( H.R. 2608 ). In addition to focusing on PFAS, several bills proposed in the 116 th Congress look more broadly at how to address CECs. For example, some aim to improve federal coordination and research and support states in addressing emerging contaminants. S. 1507 , S. 1251 , and Sections 6741-6742 of S. 1790 would direct the White House Office of Science and Technology Policy to establish a National Emerging Contaminant Research Initiative. The bills would also direct EPA to develop a program to provide technical assistance and support to states for testing and analysis of emerging contaminants and establish a database of resources available through the program to assist states with testing for emerging contaminants. While these efforts are more focused on CECs in drinking water, the bill directs the EPA to ensure that the database is available to groups that have interest in emerging contaminants, including wastewater utilities. Conclusion While Congress is currently debating how to best address the concerns related to widespread detections of PFAS, attention to other emerging contaminants (e.g., microplastics and algal toxins) has also increased with the availability of new detection methods and increased monitoring. Observers note that in the coming years, other CECs will likely emerge and prompt similar calls for immediate action to protect public health and the environment. Many observers argue that federal actions to address CECs currently tend to be reactive rather than proactive. Many of these observers assert that more focus and attention is needed on assessing the toxicity of chemical substances before they are introduced into commerce. Congress is currently considering legislation to improve federal coordination and responses to CECs. Specific to the CWA, some observers advocate for oversight to identify and address potential gaps or barriers in CWA authorities and processes that make it difficult for EPA and states to quickly respond when CECs are detected. Other observers assert that EPA could better use its existing authorities to address CECs. For example, EPA has not updated its ELGs for certain industrial categories in decades. Accordingly, some observers assert that various ELGs do not reflect advancements in science or technology that could lead to new effluent limitations for CECs. Similarly, some stakeholders assert that EPA could better prioritize which CECs warrant water quality criteria development. EPA's ability to address these and other recommendations depends on the availability of resources, treatment technologies, and scientific and economic data. Moving forward, Congress may be interested in evaluating EPA appropriations for the CWA programs that support EPA's efforts to address discharges of CECs. Congress may also be interested in overseeing the Administration's implementation of these programs.


Introduction Over the past two years, increasing migration across the Southwest border of the United States has posed considerable challenges to U.S. federal agencies charged with apprehending and processing unauthorized migrants. From FY2000 to FY2017, unauthorized migration flowsâmeasured in this report by the number of migrants apprehended by the Department of Homeland Security's (DHS's) Customs and Border Protection (CBP)âhad been generally declining. Apprehensions statistics historically have been used as a rough measure of trends in unauthorized migration flows, as well as a rough indicator of border enforcement (see " Interpreting Apprehensions Data " below). After reaching an all-time peak of 1,643,679 in FY2000, apprehensions fell to a 45-year low of 303,916 in FY2017. In FY2018 apprehensions increased to 396,579, and in FY2019 they more than doubled to 851,508. The Administration and some Members of Congress have characterized the recent increases as a border security and humanitarian crisis. For example, then-CBP Commissioner Kevin McAleenan, in testimony to the Senate Judiciary Committee on March 6, 2019, stated I have heard a number of commentators observe that even with these alarming levels of migration, the numbers are lower than the historical peaks, and as a result, they suggest what we are seeing at the border today is not a crisis. I fundamentally disagree. From the experience of our agents and officers on the ground, it is indeed both a border securityâand a humanitarianâcrisis. What many looking at total numbers fail to understand is the difference in what is happening now in terms of who is crossing, the risks that they are facing, and the consequences for our system. The difference McAleenan cited refers to the characteristics of apprehended migrants at the Southwest borderâtheir origin countries, demographic characteristics, and migratory motivationsâall of which have changed considerably during the past decade. In prior decades, unauthorized migrant flows involved predominantly adult male Mexicans, whose primary motivation was U.S. employment. If apprehended, they were typically processed through expedited removal and quickly repatriated. Relatively few migrants applied for humanitarian immigration relief such as asylum. Mexican migrants now make up a minority of total apprehensions. Sizable numbers of migrants from the "Northern Triangle"âthe Central American countries of El Salvador, Guatemala, and Hondurasânow make up the largest group. Smaller numbers of migrants are also arriving at the Southwest border from South America (e.g., Venezuela, Peru), the Caribbean (e.g., Cuba), Africa (e.g., Cameroon, Uganda), Central Asia (e.g., Uzbekistan), and South Asia (e.g., India, Bangladesh), among other regions. Instead of being dominated by adult males, migrant flows over the course of this decade have been increasingly characterized by migrants traveling as families (family units) and unaccompanied alien children (UAC). While a sizeable proportion of unauthorized migrants seek U.S. employment, a growing proportion of arriving migrants are seeking asylum and protection from violence. Studies of recent migration trends cite persistent poverty, inequality, demographic pressure related to high population growth, vulnerability to natural disasters, high crime rates, poor security conditions, and the lack of a strong state presence as factors that "push" migrants to make the risky and often dangerous journey from the Northern Triangle. "Pull" factors include the increasing use of U.S. asylum policy that, until recently, allowed most asylum seekers to remain in the United States while they awaited a decision on their cases. Lengthy court backlogs allow migrants admitted to the United States the opportunity to reunite with family members and acquire work authorization, typically six months after U.S. admission. Motivations for leaving Northern Triangle countries and choosing the United States are often a mixture of these push and pull factors, which can be interconnected, especially for families and unaccompanied children. Some observers argue that the recent migrant flows represent a failure of the rule of law. They question the legitimacy of asylum claims being made by recent unauthorized migrants and contend that many are abusing U.S. immigration laws bestowing humanitarian relief in order to gain entry into, or permission to remain in, the United States. Other observers characterize the recent migrant flows as a legitimate international humanitarian crisis resulting from violent and lawless circumstances in migrants' countries of origin. These observers contend that the "crisis" at the border reflects the inability of U.S. federal agencies to adequately process arriving migrants and adjudicate their claims for immigration relief. The changing character of the migrant flow has reportedly produced a number of logistical and resource challenges for federal agencies. These include a general capacity shortfall in CBP holding facilities, lack of appropriate facilities to detain families in ICE detention centers, reassignment of CBP personnel from port of entry duty to responding to migrants in processing facilities, and lengthy immigration court backlogs that delay expeditious proceedings. During migration peaks, these resource constraintsâcoupled with legal restrictions on the length of time that some migrants may be held âhave forced DHS to release migrants who have entered the United States unlawfully, particularly those in family units, rather than detaining or removing them. In response to the large increase in arrivals of migrants without proper entry documents, the Trump Administration has initiated changes to existing policy for apprehended migrants, largely designed to discourage these unauthorized migration flows. In January 2019, the Administration implemented the Migrant Protection Protocols (MPP), also known as the "remain in Mexico" immigration policy, which allow DHS to return applicants for admission to the United States to the contiguous country from which they arrived (on land) pending removal proceedings. The MPP sends migrants back to Mexico to await their court proceedings for the duration of their case. This program requires the coordination and assistance of the government of Mexico, a country facing its own high levels of unauthorized migration on its southern border. The program is currently operating in six border locations. Understanding changing migration patterns over the past decade may help inform Congress as it considers immigration-related legislation. This report discusses recent migrant apprehension trends at the Southwest border. It describes how unauthorized migration to the United States has changed in terms of the absolute numbers of migrants as well as their origin countries, demographic composition, and primary migratory motivations. The report concludes with a brief discussion of related policy implications. Changing Migration and Apprehension Trends The Trump Administration's and Congress's responses to the changing characteristics of unauthorized migrants at the Southwest border occur within the context of border security debates. Border security has been an ongoing subject of congressional interest since the 1970s, when unauthorized immigration to the United States first registered as a serious national challenge, and it has received increased attention since the terrorist attacks of 2001. Current debates center on how best to secure the Southwest border, including how and where to place barriers and other tactical infrastructure to impede unauthorized migration as well as the deployment of U.S. Border Patrol agents to prevent unlawful entries of migrants and contraband. Securing the border while facilitating legitimate trade and travel to and from the United States is CBP's primary mission; major shifts in CBP activities can strain resources and disrupt operations. According to U.S. immigration law, foreign nationals who arrive in the United States without valid entry documentation may pursue asylum and related protections if they demonstrate a credible fear of persecution or torture in their country of origin. These migrants, along with others either apprehended or refused admission at a port of entry, appear in the statistics kept by CBP (see "Interpreting Apprehensions Data" below). While CBP's responsibilities include monitoring the Southwest and Northern land borders, as well as the Atlantic and Pacific coasts, the Southwest border with Mexico commands most of the agency's resources because of its attendant risks. The Southwest border runs for nearly 2,000 miles along the four Southwestern states of California, Arizona, New Mexico, and Texas. It is not only the locus of most unauthorized migration to the United States but also that of illicit drugs, counterfeit products, dangerous agricultural products, and trafficked children. Much of this activity occurs at U.S. ports of entry at the Southwest border, where CBP officers inspect all individuals and vehicles that seek to enter the United States. Interpreting Apprehensions Data CBP's two components that monitor the Southwest border at and between ports of entryâthe U.S. Border Patrol (USBP) and the Office of Field Operations (OFO)âcollect statistics on individuals who have crossed the border illegally and those who are denied entry. Between ports of entry, USBP agents are responsible for apprehending individuals not lawfully present in the United States. OFO officers are responsible for inspections at U.S. ports of entry and collect data on noncitizens who are denied entry to the United States at ports of entry. Migrants typically are denied entry because they are not in possession of a valid entry document or are determined "inadmissible" on one of several grounds, such as having a criminal record, being a potential public safety threat, or being a public health threat. Inadmissible migrants made up 27%, 24%, and 13% of all migrants arriving at ports of entries along the Southwest border in FY2017, FY2018, and FY2019, respectively. While the number of inadmissible migrants grew slightly from FY2018 to FY2019, their percentage share of all CBP encounters diminished compared to apprehensions, as absolute numbers of apprehensions more than doubled during that period. ( Table 1 ). Both inadmissible and apprehended migrants can be placed in the MPP program. Apprehensions statistics historically have been used as a rough measure of trends in unauthorized migration flows. The utility of these statistics for measuring border enforcement effectiveness, on the other hand, has long been considered of limited usefulness because of the unknown relationship between apprehensions and successful unlawful entries, among other reasons. Apprehensions data, by definition, do not include illegal border crossers who evade USBP agents. They also do not account for the number of potential migrants who are discouraged from attempting U.S. entry because of enforcement measures. Consequently, it is generally unclear if an increase in apprehensions results from more attempts by migrants to enter the country illegally or from a higher apprehension rate of those attempting to enter the United States illegallyâor both. However, these statistics are arguably now less relevant than in previous years as a metric of border security efforts. In the past several years, an indeterminate but sizable share of migrants who cross between U.S. ports of entry have actively sought out U.S. Border Patrol agents in order to "turn themselves in" to request asylum. In prior years, such migrants typically would have attempted to evade USBP agents. As such, CBP's classification of these migrants as apprehensions may overstate the degree to which the agency's resources, personnel, and strategies prevent migrants from crossing the border illegally and entering the United States. Total Apprehensions The number of total apprehensions has long been used as a basic measure of migration pressure and border enforcement. Total annual apprehensions at the Southwest border averaged 687,639 during the 1970s; 999,476 during the 1980s; 1,266,556 during the 1990s; and 1,020,143 during the 2000s; but then declined to 427,766 during the 2010s. Annual apprehensions reached a 45-year low in FY2017 (303,916). In FY2018, total apprehensions increased to 396,579; and in FY2019, they more than doubled to 851,508, the highest level since FY2007 (see Figure 1 ). While high relative to annual apprehensions during the past decade, the FY2019 level is lower than annual apprehension levels for 25 of the past 45 years. Thus, recent changes in the character of the migrant flows during the past decade occurred within the context of historically low numbers of apprehensions since FY2000. Apprehensions at the Southwest border initially peaked at 1.62 million in 1986, the same year that Congress enacted the Immigration Reform and Control Act (IRCA), which gave lawful permanent resident status to roughly 2.7 million unauthorized aliens residing in the United States. After declining substantially for a few years, apprehensions rose again, climbing from 0.85 million in FY1989 to an all-time high of 1.64 million in FY2000. Apprehensions generally fell after that (with the exception of FY2004-FY2006), reaching a then-low point of 327,577 in FY2011. Since that year, apprehensions have fluctuated, as noted above. Apprehensions by Country of Origin The national origins of apprehended migrants have shifted considerably during the past two decades (see Figure 2 ). In FY2000, for example, almost all of the 1.6 million aliens apprehended at the Southwest border (98%) were Mexican nationals, and relatively few requested asylum. As recently as FY2011, Mexican nationals made up 86% of all 327,577 Southwest border apprehensions in that year. That share has declined, however, and for most years after FY2013, Mexicans accounted for less than half of total apprehensions on the Southwest border. In FY2019, "other-than-Mexicans" comprised 81% of all 851,508 apprehensions. From FY2012 to FY2019, the number of Mexican nationals apprehended dropped by 37%, from 262,341 to 166,458, while the number of migrants apprehended from all other countries increased six-fold, from 94,532 to 685,050. Apprehensions by Demographic Category CBP classifies apprehended unauthorized migrants into three demographic categories: single adults, family units (at least one parent/guardian and at least one child), and unaccompanied alien children (UAC). Of the three categories, apprehensions of persons in family units have increased the most in absolute terms since FY2012, the first year for which publicly available CBP data differentiated among the three demographic categories (see Figure 3 ). In FY2012, 321,276 single adults made up 90% of the 356,873 arriving migrants apprehended at the Southwest border, while members of family units numbered 11,116, and UAC accounted for 24,481. By FY2019, however, apprehensions of persons in family units numbered 473,682, more than all family unit apprehensions from FY2012 to FY2018 combined. Together in FY2019, those persons in family units as well as UAC (76,020 apprehensions) accounted for 65% of all apprehensions while the remaining 35% (301,806) were single adults, of whom 84% were men. Approximately 48% of family units apprehended in FY2019 were headed by mothers, 44% were headed by fathers, and about 8% were headed by two parents. Apprehensions of Family Units by Country of Origin As the number of apprehensions of individuals in family units has increased in recent years, their national origins have shifted from mostly Mexican, (comprising 80% of all 11,116 family unit apprehensions in FY2012), to mostly Salvadoran, Guatemalan, and Honduran, who together made up 91% of all 457,871 such apprehensions in FY2019 (see Figure 4 ). Apprehensions of individuals in family units from El Salvador increased from 636 (6%) of all such apprehensions in FY2012 to 27,114 (35%) of all 77,674 of such apprehensions in FY2016 before declining to 54,915 (12%) in FY2019. Over the same period, the share of family unit apprehensions from Honduras (513) and Guatemala (340) each grew from less than 5% of the total in FY2012 to 188,416 and 185,233, respectively, about 39% each of the total in FY2019. By comparison, the 6,004 apprehensions of Mexicans in family units made up 1% of the total in FY2019. Notably, the percentage of persons in family units from "all other countries," has been relatively low over the same period. In absolute numbers, this category registered less than 4,000 apprehensions in all years prior to FY2019, but rose to 37,132 family unit apprehensions in FY2019 (7% of the total, the same share as in FY2012). Apprehensions of Unaccompanied Alien Children Over the past decade, the number of unaccompanied alien children apprehended at the Southwest border has increased considerably (see Figure 5 ). From FY2011 to FY2014, UAC apprehensions increased each year, and more than quadrupled from 16,067 in FY2011 to 68,541 in FY2014. From FY2014 to FY2018, UAC apprehensions fluctuated, declining to 39,970 in FY2015; increasing to 59,692 in FY2016; declining again to 41,435 in FY2017; and increasing again to 50,036 in FY2018. In FY2019, UAC apprehensions reached 76,020, a level that exceeds the previous peak in FY2014. In FY2019, approximately 30% of apprehended UAC were girls. In the past decade, the country-of-origin composition of apprehended UAC, like that of family units, has shifted from mostly Mexican to mostly Salvadoran, Guatemalan, and Honduran. For example, in FY2009 Mexican UAC (16,114) made up 82% of all 19,668 UAC apprehensions in that year, while Salvadoran (1,221), Guatemalan (1,115), and Honduran (968) UAC made up 6%, 6%, and 5%, respectively, of the total. In contrast, by FY2019 Mexican UAC (10,487) made up 14% of all 76,020 UAC apprehensions in that year, while Salvadoran (12,021), Guatemalan (30,329), and Honduran (20,398) UAC made up 16%, 40%, and 27%, respectively, of the total. Current statute treats children from contiguous countries (Mexico and Canada) differently than children from non-contiguous countries. While UAC from Mexico can be repatriated promptly through a process known as voluntary departure , UAC from all other countries are placed in formal removal proceedings. The latter are then referred to the Department of Health and Human Services' (HHS') Office of Refugee Resettlement (ORR), where they are initially sheltered and subsequently placed with family members or sponsors while they await their immigration hearing. Hence, the shift in the country-of-origin composition of the apprehended UAC population has had considerable impact on agencies charged with the processing and care of these children. Total Apprehensions by Month in FY2019 Over the past two decades, apprehensions have followed a pattern consistent with a seasonal migration cycle. In this cycle, peak numbers of apprehensions occur in the spring months (MarchâJune), followed by progressively lower numbers in the hotter summer months (JulyâSeptember), lower-than-average numbers through the fall months (OctoberâDecember), and even lower numbers in January, before rising again through the spring months when the pattern begins to repeat. During FY2019, the monthly pattern in total apprehensions at the Southwestern border was similar to the trends during the past two decades (see Figure 6 ). From the peak in May through September of FY2019, apprehensions declined nearly 70%, from approximately 133,000 to just over 40,000. These data suggest that the declines in monthly apprehensions from May to September of FY2019 stemmed primarily from declining numbers of family unit apprehensions. The number of persons in family units apprehended on a monthly basis dropped from 84,490 in May to 15,824 in September (an 81% decrease). For UAC, apprehensions declined by 72%, from 11,475 in May to 3,165 in September. Apprehensions of single adults saw a smaller decline (42%) over this period, from 36,894 in May to 21,518 in September. These patterns suggest that declining apprehensions in recent months may have resulted not only from the immigration enforcement policies of the Trump Administration but also from decades-long seasonal migration patterns, among other factors. Policy Implications This report has described the following major shifts in the composition and character of migrant flows to the Southwest border that have unfolded in less than a decade: In the past two years, the number of total apprehensions has increased substantially, a reverse of the general trend of declining and relatively low apprehension levels seen since FY2001. The unauthorized migrant flow apprehended at the Southwest border no longer consists primarily of individuals from Mexico, a country with whom the United States shares a border and close economic and historical ties. It now originates largely from El Salvador, Guatemala, and Honduras. Also, growing numbers of unauthorized migrants are originating from Africa, Asia, and the Caribbean. The unauthorized migrant flow is no longer dominated by economic migrants exclusively seeking employment. It is now driven to a larger extent than in past years by asylum seekers and others with similar motivations, such as escaping violence and domestic insecurity, who may also be interested in working in the United States. Such migrants often seek out U.S. Border Patrol agents at the border when crossing illegally between U.S. ports of entry rather than attempting to elude them. The unauthorized migrant flow no longer consists primarily of single adult migrants but rather of families and children traveling without their parents. Although not previously discussed, changing migration strategies are also altering how federal agencies respond to migrant flows. For example, migrants have been increasingly traveling in large groups, reportedly to protect themselves from harm. In addition, more migrants are arriving at remote CBP outposts along the Southwest border, sometimes overwhelming the relatively few CBP personnel who staff them. These changing patterns at the Southwest border have considerable policy implications. In comparison with apprehended single adult economic migrants from Mexico, more-recently apprehended migrants require lengthier processing and create a call for greater resources and personnel of more federal agencies. When migrants originate from countries other than the contiguous countries of Mexico and Canada, their removals involve longer processing time, higher transportation costs, and more involved inter-agency coordination. If arriving migrants are unaccompanied alien children from noncontiguous countries, they are protected from immediate removal by statutes that require them to be put into formal immigration removal proceedings and they are referred to the care and custody of ORR. If migrants seek asylum, they generally require a credible fear hearing. They may be detained in DHS facilities for varying periods and must be processed by DOJ's Executive Office for Immigration Review (EOIR). CBP, among all federal agencies, is arguably the most affected by the break with historical migration patterns. The pressures of large groups of migrants arriving together and the greater vulnerabilities of new arrivals are reportedly testing CBP's border infrastructure, agency personnel, and long-standing policies. When unauthorized migrant flows consist largely of families and children, who often arrive in large groups or at remote U.S. border locations, CBP has adjusted its operations and allocated resources and personnel to accommodate more vulnerable migrants. Some studies also suggest that smuggling guides sometimes direct migrants to cross in specific locations to outmaneuver USBP agents and infrastructure and avoid detection. Moreover, anecdotal evidence suggests migrant arrival strategies can be based upon perceptions of differences in border enforcement policies and practices among and within the nine CBP Southwest border sectors. If enforcement policies vary by sector, CBP can expect migration patterns to shift to sectors that migrants perceive as offering them the greatest chance of acquiring the immigration relief they seek. The Trump Administration has changed immigration enforcement policies and practices at the border in an attempt to reduce unauthorized migration and discourage fraudulent or frivolous claims for humanitarian immigration relief. President Trump, DHS, DOD, and DOJ have acted together with a series of policy changes that make it more difficult for migrants to be awarded asylum. For example, see the following: In November 2018, the President issued a proclamation to suspend immediately the entry into the United States of aliens who cross the Southwest border between ports of entry. This proclamation has been challenged in court and a preliminary injunction was issued by a federal district court. As noted above, DHS implemented the Migrant Protection Protocols (MPP) in January 2019, and for the past several years CBP has also used the practice of "metering" migrants. Both of these policies require migrants to wait on the Mexican side of the border. Since April 2018, National Guard personnel have supported DHS at the border, while active duty personnel began providing support in October 2018. In February 2019, President Trump proclaimed a national emergency pursuant to the National Emergencies Act in order to fund a physical barrier at the Southwest border with Mexico using $6.1 billion in funds from the Department of Defense (DOD). In September 2019, the Secretary of Defense deferred funding for military construction projects in order to redirect funds to border barrier projects using his authority under the emergency statute 10 U.S.C., Section 2808. In July 2019, DHS and DOJ jointly issued an interim final rule (IFR) that makes aliens ineligible for asylum in the United States if they arrive at the Southwest border without first seeking protection from persecution in other countries through which they transit. In addition, the United States is working with Mexico to decrease Central American migrant flows and with Central American governments to promote economic prosperity, improve security, and strengthen regional governance. The changing character of recent migrant flows at the Southwest border also may suggest that apprehensions may be less useful than in the past for measuring border enforcement. Because many apprehended migrants now actively seek out U.S. Border Patrol agents in order to request asylum, increases or decreases in apprehension numbers may not reflect the effectiveness of border enforcement strategies. Rather, an increase in apprehensions combined with the changing characteristics of recently apprehended migrants may increasingly portend greater resource needs for federal agencies because the administrative requirements for asylum claims are more resource-intensive than those for unauthorized migrants who do not request asylum and are quickly repatriated through expedited removal. The challenge of deterring unauthorized migrants from entering the United States has been complicated and overshadowed by the challenge of processing, in a fair and timely manner, relatively greater numbers of migrants seeking asylum. Recent migration research suggests that forced migration from civil conflict, violence, weather events, and climate change is playing a more prominent role in worldwide migratory patterns. To some extent, patterns described in this report are consistent with that trend. Declining birth rates in parts of Latin America and improving employment prospects in Mexico over the past decade have reduced the relative proportion of single adult migrants whose primary motivation is U.S. employment. In contrast, relatively high levels of violence and lack of public security, among other factors, have increased the relative proportion of Central American and Mexican families and children whose primary migratory motivation is humanitarian relief. Options for Congress could include legislative responses to the series of policies that the Administration has developed to address the changing flow of migrants at the Southwest border. Some proposals may consider changes to the appropriations of agencies charged with processing unauthorized migrants to reshape the system from one that was designed to apprehend and return single unauthorized adults from Mexico with no claims for protection, to one that can more quickly adjudicate those seeking humanitarian protection. Other options may include greater supervision of unauthorized migrants who are released into the United States, and mandating the collection and publication of more-detailed and timely data from DHS to more completely assess the flow of unauthorized migrants, including those in the MPP program, and their impact on border enforcement and the immigration court system.


Introduction Paid family leave (PFL) refers to partially or fully compensated time away from work for specific and generally significant family caregiving needs, such as the arrival of a new child or serious illness of a close family member. Although the Family and Medical Leave Act of 1993 (FMLA; P.L. 103-3 ) provides eligible workers with a federal entitlement to unpaid leave for a limited set of family caregiving needs, no federal law requires private-sector employers to provide paid leave of any kind. Currently, employees may access PFL if offered by an employer. In addition, some states have created family leave insurance (FLI) programs, which provide cash benefits to eligible workers who engage in certain (state-identified) family caregiving activities. In these states, workers can access PFL by combining an entitlement to unpaid leave with state-provided insurance benefits. Some Congressional proposals to expand national access to paid family leave expand upon these existing mechanisms. A new tax credit, created in December 2017 ( P.L. 115-97 ), seeks to expand voluntary employer-provided PFL, and—similar to the state insurance approach—the Family and Medical Insurance (FAMILY Act; S. 463 / H.R. 1185 ), which proposes to create a national wage insurance program for persons engaged in family caregiving activities or who take leave for their own serious health condition. The New Parents Act ( S. 920 / H.R. 1940 ) would allow parents of a new child to receive Social Security benefits, to be repaid at a later date, for the purposes of financing parental leave. Others proposals, such as the Working Parents Flexibility Act of 2019 ( H.R. 1859 ) and the Freedom for Families Act ( H.R. 2163 ), would amend the tax code to provide tax-advantages to individuals with caregiving responsibilities. Members of Congress who support increased access to paid leave generally cite as their motivation the significant and growing difficulties some workers face when balancing work and family responsibilities, and the financial challenges faced by many working families that put unpaid leave out of reach. In general, expected benefits of expanded access to PFL include stronger labor force attachment for family caregivers and greater income stability for their families, and improvements to worker morale, job tenure, and other productivity-related factors. Potential costs include the financing of payments made to workers on leave, other expenses related to periods of leave (e.g., hiring a temporary replacement or productivity losses related to an absence), and administrative costs. The magnitude and distributions of costs and benefits will depend on how the policy is implemented, including the size and duration of benefits, how benefits are financed, and other policy factors. This report provides an overview of paid family leave in the United States, summarizes state-level family leave insurance programs, notes PFL policies in other advanced-economy countries, and notes recent federal legislative action to increase access to paid family leave. Paid Family Leave in the United States Throughout their careers, many workers encounter a variety of family caregiving obligations that conflict with work time. Some of these are broadly experienced by working families but tend to be short in duration, such as episodic child care conflicts, school meetings and events, routine medical appointments, and minor illness of an immediate family member. Others are more significant in terms of their impact on families and the amount of leave needed, but occur less frequently in the general worker population, such as the arrival of a new child or a serious medical condition that requires inpatient care or continuing treatment. Although all these needs for leave may be consequential for working families, the term family leave is generally used to describe the latter, more significant, group of needs that tend to require longer periods of time away from work. As defined in state law and federal proposals, family caregiving activities that are eligible for PFL or leave insurance benefits generally include caring for and bonding with a newly arrived child and attending to the serious medical needs of certain close family members; some also allow leave or benefits for workers with certain military family needs. In practice, day-to-day needs for leave to attend to family matters (e.g., a school conference or lapse in child care coverage), minor illness (e.g., common cold), or preventive care are not included among family leave categories. Employer-Provided Paid Family Leave Employer-provided PFL in the private sector is voluntary. According to a national survey of employers conducted by the Bureau of Labor Statistics (BLS), 16% of private-industry employees had access to PFL (separate from other leave categories) through their employer in March 2018. These statistics, displayed in Table 1 , further show that PFL was more prevalent among managerial and professional occupations; information, financial, and professional and technical service industries; high-paying occupations; full-time workers; and workers in large companies (as measured by number of employees). Recent announcements by several large companies suggest that access may be increasing among certain groups of workers. Among new company policies announced in recent years, some emphasize parental leave (i.e., leave taken by mothers and fathers in connection with the arrival of a new child), and others offer broader uses of family leave. A 2017 study by the Pew Research Center (Pew) examined U.S. perceptions of and experiences with paid family and medical leave; its results provide insights into the need for such leave among U.S. workers and its availability for those who need it. Pew reports, for example, that 27% of persons who were employed for pay between November 2014 and November 2016 took leave (paid and unpaid) for family caregiving reasons or their own serious health condition over that time period, and another 16% had a need for such leave but were not able to take it. Among workers who were able to use leave, 47% received full pay, 36% received no pay, and 16% received partial pay. Consistent with BLS data, the Pew study indicates that lower-paid workers have less access to paid leave; among leave takers, 62% of workers in households with less than $30,000 in annual earnings reported they received no pay during leave, whereas this figure was 26% among those with annual household incomes at or above $75,000. State-Run Family Leave Insurance Programs Some states have enacted legislation to create state paid FLI programs, which provide cash benefits to eligible workers who engage in certain caregiving activities. Four states—California, New Jersey, New York, and Rhode Island—have active programs. Three additional programs—those in the District of Columbia (DC), Washington State, and Massachusetts—await implementation. Table 2 summarizes key provisions of state FLI laws and shows the following: The maximum weeks of benefits available to workers and wage replacement rates vary across states. Existing state FLI programs offer between 4 weeks (Rhode Island) and 10 weeks (New York) of benefits. Starting July 1, 2020, New Jersey is to increase benefit weeks from 6 to 12. When its plan is implemented, DC is to offer 8 weeks of paid family leave in 2020, and Washington State is to offer 12 weeks of paid family leave in the same year. New York's entitlement is to increase to 12 weeks of benefits when its plan is fully implemented in 2021. Massachusetts is to provide up to 12 weeks for family leave, unless leave is used to provide care to a seriously ill or injured military service member, when up to 26 weeks may be used. Program eligibility typically involves in-state employment of a minimum duration, minimum earnings in covered employment, or contributions to the insurance funds. All state FLI programs currently in operation are financed entirely by employee payroll tax receipts; however, when implemented, the DC program is set to be financed by employers. Massachusetts' and Washington State's programs are to be jointly financed by employers and employees, with some exceptions. Some FLI programs (e.g., Rhode Island) provide job protection directly to workers who receive FLI benefits, meaning that employers must allow a worker to return to his or her job after leave has ended. Workers in other states may receive job protection if they are entitled to leave under federal or state family and medical leave laws, and coordinate such job-protected leave and FLI benefits. Paid Family Leave in OECD Countries Many advanced-economy countries entitle workers to some form of paid family leave. Whereas some provide leave to employees engaged in family caregiving (e.g., of parents, spouse, and other family members), many emphasize leave for new parents, mothers in particular. As of 2016, the Organization for Economic Co-operation and Development (OECD) family leave database counts 34 of its 35 members as providing some paid parental leave (i.e., to care for children) and maternity leave, with wide variation in the number of weeks and rate of wage replacement across countries. This is shown in Figure 1 , which plots the OECD's estimates of weeks of full-wage equivalent leave available to mothers. Weeks of full-wage equivalent leave are calculated as the number of weeks of leave available multiplied by the average wage payment rate. For example, a country that offers 12 weeks of leave at 50% pay would be said to offer 6 full-wage equivalent weeks of leave (i.e., 12 weeks x 50% = 6 weeks). A smaller share (27 of 35) of OECD countries provides paid leave to new fathers. In some cases, fathers are entitled to less than a week of leave, often at full pay (e.g., Greece, Italy, and the Netherlands), whereas others provide several weeks of full or partial pay (e.g., Portugal provides five weeks at full pay, and the United Kingdom provides two weeks at an average payment rate of 20.2%). Some countries provide a separate entitlement to fathers for child caregiving purposes. This type of parental leave can be an individual entitlement for fathers or a family entitlement that can be drawn from by both parents. In the latter case, some countries (e.g., Japan, Luxembourg, and Finland) set aside a portion of the family entitlement for fathers' use, with the goal of encouraging fathers' participation in caregiving. Figure 2 summarizes paid leave entitlements reserved for fathers in OECD countries in 2016; it plots the OECD's estimates of weeks of full-wage equivalent paternity leave and parental leave reserved for fathers. The OECD examined the availability of family caregiver leave among its member countries in 2011 and found that of the 25 countries for which it could identify information, 14 had polices providing paid leave to workers with ill or dying family members; these are summarized in Table 3 . Qualifying needs for leave, leave entitlement durations, benefit amounts, and eligibility conditions varied considerably across the countries included in the OECD study. Recent Federal PFL Legislation and Proposals The overarching goal of PFL legislative activity in the 116 th Congress has been to increase access to leave by reducing the costs associated with providing or taking leave. The Strong Families Act, which became law in December 2017 ( P.L. 115-97 ), allows employers to claim tax credits for a portion of wages paid to certain employees taking family or medical leave; this approach potentially increases access to PFL for workers while reducing the costs to employers of providing the leave. A second approach addresses costs incurred by workers taking leave. For example, the establishment of a national family leave insurance program, such as that proposed in the Family and Medical Insurance Leave Act (FAMILY Act; S. 463 / H.R. 1185 ), would provide cash benefits to eligible individuals who are engaged in certain caregiving activities, potentially making the use of unpaid leave (e.g., as provided by FMLA or voluntarily by employers) affordable for some workers. Proposals such as the New Parents Act ( S. 920 / H.R. 1940 ) would allow eligible new parents to receive to up to three months of Social Security benefits, in return for deferring retirement (or early retirement) by a period of time determined by the Social Security Administration to cover the costs of the parental benefit. Other approaches include proposals to create tax-advantaged parental leave savings accounts (e.g., the Working Parents Flexibility Act of 2019, H.R. 1859 ) and tax-advantaged distributions from health savings accounts for family and medical leave purposes (e.g., the Freedom for Families Act, H.R. 2163 ). In addition, the President's FY2020 budget proposes to provide six weeks of financial support to new parents through state unemployment compensation (UC) programs. A similar approach was taken in 2000 by the Clinton Administration, which—via Department of Labor regulations—allowed states to use their UC programs to provide UC benefits to parents who take unpaid leave under the FMLA, other approved unpaid leave, or otherwise take time off from employment after the birth or adoption of a child. The Birth and Adoption Unemployment Compensation rule took effect in August 2000, and it was later removed from federal regulations in November 2003.