This report presents a side-by-side comparison of H.R. 2576 , the TSCA Modernization Act of 2015, as passed by the House on June 23, 2015, and S.Amdt. 2932 , the Frank R. Lautenberg Chemical Safety for the 21 st Century Act, as passed by the Senate on December 17, 2015, as a substitute amendment to H.R. 2576 . (Hereafter in this report, the House-passed bill H.R. 2576 will be referred to as the "House bill," while the Senate amendment to H.R. 2576 will be referred to as the "Senate amendment.") Both the House bill and the Senate amendment would amend Title I of the Toxic Substances Control Act (TSCA). The Senate amendment, but not the House bill, would also amend the Mercury Export Ban Act of 2008 and add a provision to the Public Health Service Act regarding potential cancer clusters. The first section of this report provides a brief background on Title I of TSCA. For a summary of TSCA provisions and history, see CRS Report RL31905, The Toxic Substances Control Act (TSCA): A Summary of the Act and Its Major Requirements , by [author name scrubbed]. The second section describes differences between the House bill and the Senate amendment and also presents background on selected issues that the legislation addresses. The final section includes Table 1 , which presents a side-by-side comparison of the provisions of existing law, the House bill, and the Senate amendment. In 1976, President Ford signed into law the Toxic Substances Control Act, which authorizes the U.S. Environmental Protection Agency (EPA) to identify and regulate chemicals in U.S. commerce that present an "unreasonable risk of injury to health or the environment." Since 1976, Congress has added five other titles to TSCA and has amended the original law, referred to as Title I, to address specific chemical concerns. None of these additions and amendments has altered the core program under Title I of TSCA. Neither the House bill nor the Senate amendment would amend the other titles (i.e., Titles II through VI) of TSCA. Among other things, Title I of TSCA requires EPA to compile and maintain a list of chemical substances manufactured or processed in the United States. This list is referred to as the TSCA Chemical Substance Inventory (or TSCA Inventory). EPA's initial compilation of the TSCA Inventory included over 62,000 chemical substances. TSCA distinguishes between chemical substances that are on the inventory and those that are not. Any chemical substance listed on the inventory is considered by the agency as an "existing" chemical substance. The statute defines any chemical substance not on the inventory as a "new chemical substance." Since EPA's publication of the initial TSCA inventory, the agency has added over 23,000 new chemical substances to the inventory. Once a chemical substance is added to the TSCA inventory, it becomes an existing chemical substance for purposes of the statute. In order to determine which chemicals warrant regulation under TSCA, EPA is authorized to evaluate risks that may arise from the entire commercial life-cycle of chemicals, including their manufacture, processing, distribution, use, and disposal. Pursuant to TSCA Section 6, EPA has authority to pursue a range of regulatory options to address unreasonable risks from chemicals. These options vary in severity from a complete ban to a requirement that manufacturers notify distributors of unreasonable risks. Since the enactment of TSCA, EPA has regulated few chemicals under TSCA Section 6, including: chlorofluorocarbons used in aerosol propellants; nitrosamines used in metalworking fluids (40 C.F.R. Part 747); hexavalent chromium used for certain water cooling towers (40 C.F.R. Part 749); new uses of asbestos (40 C.F.R. Part 763, Subpart I); dioxin-contaminated wastes; and polychlorinated biphenyls (40 C.F.R. Part 761). The agency has taken actions pursuant to other authorities in the statute. For example, EPA has: collected information on the risks, uses, and volumes in commerce of various chemicals to inform its evaluation of chemical risks (pursuant to TSCA Sections 4, 5, and 8); evaluated various chemicals for risks (pursuant to TSCA Section 6); and promulgated rules to require notification for significant new uses of certain chemical substances (pursuant to TSCA Section 5). Since 2005, Members of Congress have introduced bills to revise the chemical evaluation process for determining whether regulatory actions are warranted and to address other related purposes. Although the bills were not enacted, they generated debate on whether and how to amend the evaluation process, regulatory criteria, and other elements of the law. The House bill would amend several provisions in TSCA, including: the authority for EPA to require testing of chemicals under TSCA Section 4; the process by which EPA would evaluate risks of chemicals and regulate those found to present unreasonable risks under TSCA Section 6; the procedures and standards under TSCA Section 14 for confidential treatment of certain information submitted to EPA under TSCA; TSCA's relationship to state laws regulating chemicals under TSCA Section 18; and the authority for EPA to collect fees under TSCA Section 26. The Senate amendment would amend the same provisions of TSCA listed above, albeit with differences. Additionally, the Senate amendment would amend: the process by which EPA reviews new chemical substances or significant new uses of chemicals under TSCA Section 5; the recordkeeping and reporting requirements under TSCA Section 8; and various other provisions. The following sections provide a brief discussion of seven issues that have received attention in the debate to amend Title I of TSCA. The discussions include comparisons between how the House bill and Senate amendment would address each issue. These issues include: prioritization of existing chemical substances for the evaluation of risks; regulatory threshold criteria under which EPA would be authorized to restrict a chemical; regulatory options available to EPA in restricting a chemical found to warrant regulation; EPA's authority to require the development of new information regarding a chemical; preemption of state laws concerning the regulation of chemicals; disclosure and protection from disclosure of information submitted to EPA; and resources that may be available for EPA to administer the act. Determining which chemicals EPA may select before others to evaluate risks has been a long-standing issue given that the agency has finite resources to evaluate over 85,000 chemical substances listed on the TSCA inventory and continues to become aware of new chemical substances. EPA's evaluation of a chemical is intended to generate information that informs the agency's determination as to whether the regulatory threshold is met to restrict that chemical. Under TSCA, EPA has discretion over which chemicals on the TSCA inventory to evaluate for risks. In 2012, EPA identified, as part of the agency's TSCA Work Plan, more than 1,200 substances that possibly warranted an evaluation based on certain prioritization criteria. These substances were further screened based on hazard, exposure, and bioaccumulation potential, which led EPA to prioritize 90 substances for an evaluation of risks to human health or the environment. Of the 90 prioritized chemical substances, EPA has assessed five, three of which were determined to present risks. EPA continues to evaluate the other 85 substances. For new chemical substances, TSCA Section 5 requires manufacturers to submit a premanufacture notice (PMN) to EPA 90 days prior to manufacturing the chemical substance, subject to certain exemptions. During this time period, EPA has the opportunity to evaluate risks of the new chemical substance and determine whether regulation may be warranted based on the PMN and any existing data concerning the environmental and health effects of the substance. According to EPA, from July 1979 through September 2015, the agency has received more than 39,000 PMNs and more than 15,000 PMN exemption applications. EPA states that it has taken regulatory action on approximately 10% of the PMNs submitted. Both the House bill and the Senate amendment would establish a process and criteria for EPA to prioritize existing chemical substances for evaluation, albeit with differences. The Senate amendment, and not the House bill, would amend TSCA Section 5 with regard to the evaluation of new chemical substances, although, in part, it would codify certain existing practices. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see pages CRS-28 and CRS-36 in Table 1 . In order for EPA to restrict a chemical under TSCA, the agency must first determine that the chemical presents or will present "an unreasonable risk of injury to [human] health or the environment." This phrase is used in multiple provisions of TSCA as the basis for whether certain actions may be warranted. Some stakeholders have argued that the existing regulatory threshold for restricting a chemical in TSCA—that the chemical presents or will present risks that are unreasonable—is difficult for EPA to demonstrate. A recurring issue of concern in the TSCA debate has been whether or how to amend the regulatory threshold to clarify the criteria and factors to be considered for determining whether certain chemicals warrant regulatory control. TSCA does not define the "unreasonable risk" standard. However, the "unreasonable risk" standard of TSCA has been interpreted at the circuit court level as, essentially, a multi-factor balancing test. In its 1991 decision, Corrosion Proof Fittings v. EPA , which struck down large parts of an asbestos ban under TSCA, the Fifth Circuit stated that "[i]n evaluating what is 'unreasonable,' the EPA is required to consider the costs of any proposed actions and to 'carry out this chapter in a reasonable and prudent manner [after considering] the environmental, economic, and social impact of any action.'" The court also quoted a Supreme Court case regarding "unreasonable risk" language in general, saying that "'unreasonable risk' statutes require 'a generalized balancing of costs and benefits.'" The Fifth Circuit ruled that in its asbestos ban, EPA had "basically ignored the cost side of the TSCA equation" and that potentially "spending $200-$300 million to save approximately seven lives (approximately $30-$40 million per life) over thirteen years" was not reasonable under the "unreasonable risk" standard. Thus, under TSCA's "unreasonable risk" standard, whether regulation of a chemical is warranted depends on not only the hazards of the chemical and the extent or likelihood of exposure to the chemical but also the costs of risk management and the benefits of various uses of the chemical. Since 1991, EPA has not promulgated a rule to restrict a chemical under TSCA Section 6. Both the House bill and the Senate amendment would amend the regulatory threshold for restricting a chemical by modifying what constitutes "unreasonable risk." As an example, both the House bill and the Senate amendment would prohibit the consideration of cost and other non-risk factors when determining whether there are unreasonable risks associated with a chemical. However, whether more chemicals could be regulated under TSCA by amending the regulatory threshold would ultimately depend on implementation. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see page CRS-31 in Table 1 . If EPA were to determine that a chemical presents or will present "an unreasonable risk of injury to health or the environment," TSCA Section 6 directs the agency to promulgate a requirement to protect adequately against such risks using the "least burdensome requirement" while considering certain other factors. These include, among other factors, the approximate costs of the proposed regulation and the availability of alternatives to the chemical subject to regulatory control. EPA may select the least burdensome requirement from options listed in the statute that vary in severity from a complete ban to a requirement that manufacturers or processors notify distributors, other people in possession of a chemical, and the general public of unreasonable risks. This provision implements the concept of balancing costs and benefits when determining what requirement to impose on a chemical determined to meet the regulatory threshold. Some stakeholders have argued that the limit on EPA to choose the least burdensome regulatory requirement that still adequately protects against unreasonable risk requires the agency to do lengthy analyses and may result in the promulgation of a regulation that is inadequately protective because of considerations of cost. In Corrosion Proof Fittings v. EPA , the Fifth Circuit stated that EPA had not shown substantial evidence that its total ban on most uses of asbestos was the least burdensome adequate alternative for all circumstances and product categories. Thus, in practice, the "least burdensome" requirement imposes an additional standard on EPA beyond that imposed by the requirement that the agency conduct a cost-benefit analysis of the chosen alternative, because a rule cannot be upheld based only on its benefits outweighing its costs. In order to reject a less burdensome requirement in favor of a more burdensome one, the Fifth Circuit required EPA to show that each less burdensome requirement would not adequately protect against the unreasonable risk. Some environment and public health groups have argued that it is unlikely another chemical could be regulated under TSCA if EPA was not able to regulate asbestos under the statute. Both the House bill and the Senate amendment would remove from TSCA the requirement that EPA promulgate the "least burdensome requirement" in order to restrict a chemical demonstrated by the agency to present unreasonable risks. In addition, the House bill and the Senate amendment would amend the process that EPA would undertake to select a regulatory option that would restrict a chemical determined to warrant regulation. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see page CRS-31 in Table 1 . EPA relies on scientific and technical information regarding chemical substances and mixtures to evaluate risks and determine if any risks are unreasonable. In order to obtain such information, TSCA Section 8 authorizes EPA to require reporting and recordkeeping of existing information on chemical substances and mixtures by manufacturers, processors, and distributors of chemical substances. If the risks are insufficiently known from existing information and testing is necessary to develop new information about the risks, TSCA Section 4 mandates that EPA promulgate a rule to require manufacturers and processors to conduct testing if the agency finds (1) that the chemical substance may present unreasonable risks, or (2) that "substantial quantities" are or will be produced either in a way that enters or may reasonably be anticipated to enter the environment, or in a way that "there is or may be significant or substantial human exposures." To date, EPA has required additional testing for over 200 chemical substances. Some stakeholders have argued that limits on EPA's authority under TSCA to require the development of new information regarding the health and environmental effects of chemicals have hindered EPA's ability to assess the risks of chemicals. EPA has argued that finding a chemical substance "may present an unreasonable risk of injury to health or the environment" in order to require the development of new information to determine whether a chemical substance presents an unreasonable risk is a "possible analytical catch-22." Likely for this reason, EPA has generally required further testing based on the production volume of a chemical and the likelihood of exposure. Some stakeholders contend that the development of new information may take a lengthy amount of time and be costly to those required to develop the information. Both the House bill and the Senate amendment would expand EPA's authority to require the development of test data, albeit with differences in the extent of that authority. As an example, the House bill would authorize EPA to require testing if the agency finds that testing of the chemical is necessary to evaluate risks to determine whether regulation is warranted under TSCA. Compared to existing TSCA, this finding would be an additional finding that EPA could make to require testing. As another example, the Senate amendment would give EPA discretion to require testing that the agency determines is necessary for specific purposes related to evaluating risks of chemicals. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see page CRS-18 in Table 1 . With an increasing number and diversity of state chemical regulations providing a backdrop for TSCA amendment discussions at the federal level, the scope of TSCA preemption has been a long-standing issue. Under the Supremacy Clause of the U.S. Constitution, conflicting state law and policy must yield to the exercise of Congress's enumerated powers. When it acts, Congress can preempt state action within a field entirely, allow states to take different actions, or permit state action to any degree in between. Current TSCA preemption is not at either end of the spectrum; it gives EPA a primary role in management of chemicals but leaves states some ability to set their own chemical requirements under certain circumstances. Specifically, TSCA Section 18 provides that states are generally preempted from taking action to manage risk from a chemical if EPA has taken action on a similar risk presented by that chemical, although states may apply for waivers. For state requirements other than duplicative testing requirements, a number of exceptions to preemption apply. State requirements that are identical to federal requirements are not preempted, allowing states to co-enforce the federal requirements by adopting them as their own law. States are also authorized to regulate disposal, establish or continue in effect any chemical requirement adopted under the authority of any other federal law, and prohibit use of a chemical within the state (except for its upstream use in manufacture or processing of other chemicals). In the TSCA amendment context, advocates for broader federal preemption claim that a uniform national regulatory framework with regard to chemicals can provide sufficient protection from chemical risks. They assert that absent preemption, states may implement varying and even conflicting regulations, leading to increased compliance costs, reduced economies of scale, and economic repercussions across industry supply chains and throughout interstate commerce. On the other hand, opponents of preemption argue that the federal regulation should set a minimum standard but that states should be able to experiment with different policies and implement more stringent requirements than those EPA sets in order to protect the safety and welfare of their citizens. Both the House bill and the Senate amendment would retain the general structure of TSCA preemption, in which certain EPA actions regarding a specific chemical will preempt state chemical regulations for that same chemical, subject to exceptions and waivers. Both would add some exceptions to preemption and would align the preempting EPA actions with the amended regulatory framework but with some differences between their approaches. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see pages CRS-42 through CRS-46 in Table 1 . TSCA requires chemical manufacturers, processors, and distributors to submit certain information to EPA regarding their chemicals. This information can include detailed chemical structures, production volumes, and health and safety data. Thus, another issue of concern in amending TSCA is how to balance the goals of, on the one hand, public access to chemical information and, on the other, protection of information that if disclosed could compromise the submitter's competitiveness. TSCA Section 14 prohibits disclosure of information reported to or obtained by EPA that is exempt from disclosure under the Freedom of Information Act (FOIA) as "trade secrets and commercial or financial information obtained from a person and privileged or confidential," with certain exceptions. Under the terms of TSCA, wrongful disclosure by EPA employees or contractors is a criminal act. Confidential business information (CBI) protection under TSCA does not prohibit disclosure of any health and safety study, but any data within any such study that would disclose manufacturing processes or proprietary mixture compositions would remain protected. Many items of information—including chemical identities—have been protected by EPA as CBI on the TSCA Inventory, in health and safety studies, and in other situations. TSCA Section 14 contains several exceptions requiring disclosure of CBI, including if EPA determines that disclosure is "necessary to protect health or the environment against an unreasonable risk of injury." If EPA makes this determination, or if EPA finds that information that has been designated as CBI does not meet the standard for protection, EPA must provide notice to the information submitter prior to disclosing the information. Procedurally, to obtain CBI protection for information that the submitter believes is entitled to confidential treatment, the submitter is required only to designate the information as CBI. Neither substantiation nor EPA review of confidentiality claims is expressly required under current TSCA. CBI protection also continues indefinitely, unless EPA determines that the information no longer qualifies for protection under the FOIA exemption and gives the submitter the required prior notice. Since 2010, EPA has increased its review of confidentiality claims, particularly relating to chemical identities in health and safety studies. The agency has also issued a "CBI Declassification Challenge" asking industry to withdraw CBI claims voluntarily and has engaged in other initiatives to increase public access to non-confidential information. Both the House bill and the Senate amendment would expand the requirements for substantiation of confidentiality claims and add certain circumstances (such as emergencies) when confidential information may be disclosed, with some differences. The House bill and the Senate amendment also take somewhat differing approaches to protecting chemical identities in health and safety studies. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see pages CRS-20 through CRS-27 in Table 1 . The level of resources and staffing available to EPA is one key factor that affects the pace and thoroughness for evaluating chemicals under TSCA. An issue for Congress is whether to continue funding EPA's activities under TSCA through discretionary appropriations or to establish dedicated sources of funding that are supplemental to and not subject to discretionary appropriations. Under TSCA Section 29, appropriations for Title I were authorized through FY1983. Congress has continued to fund EPA's implementation of TSCA through annual appropriations pursuant to the program or "organic" authorities of TSCA that do not have a sunset date and do not expire unless otherwise amended. Additionally, TSCA Section 26(b) authorizes EPA to assess fees on chemical manufacturers (including importers) or processors. The authorization for EPA to assess these fees does not have a sunset date. EPA's authority to collect fees is statutorily limited to a maximum of $2,500 for the following actions required under TSCA Section 5: Each PMN that a manufacturer of a new chemical substance is required to submit to EPA, and Each notice that a manufacturer or processor is required to submit to EPA for a significant new use of a chemical substance. TSCA Section 26(b) currently provides an exception for small businesses under which these fees are limited to a maximum of $100. Furthermore, TSCA Section 26(b) authorizes EPA to assess fees within these statutory caps for the costs of evaluating testing data that a manufacturer or processor of a chemical substance may be required to submit to the agency under TSCA Section 4. Under TSCA, there is no dedicated account for fees collected under Section 26(b). As such, these fees are treated as miscellaneous receipts and deposited into the General Fund of the U.S. Treasury as required by the Miscellaneous Receipts Act. The availability of fees collected under TSCA for obligation by EPA is subject to annual appropriations. Both the House bill and the Senate amendment would amend TSCA Section 26(b) with regard to the authority to collect fees. The House bill and the Senate amendment differ in terms of what activities EPA would be authorized to collect a fee from manufacturers or processors and certain other limitations to overall fee collection authority. For either the House bill or the Senate amendment, collected fees would only be made available to EPA subject to the discretionary appropriations process. For a comparison among existing law, the House bill, and the Senate amendment on this topic, see pages CRS-47 through CRS-48 in Table 1 . Table 1 of this report presents a side-by-side comparison of existing law, the House bill, and the Senate amendment. The table includes a discussion of each provision of the House bill and the Senate amendment, although it does not provide comprehensive analysis of the potential effects of particular provisions in the House bill or the Senate amendment. Existing law in the table is presented to the extent that such law would be amended by either the House bill or the Senate amendment. The table organizes the provisions of the House bill and the Senate amendment under 10 subheadings selected by CRS that reflect the following elements of TSCA: 1. Short title, intent, and definitions (page CRS- 12 ); 2. Policies, procedures, and guidance; and advisory committee (page CRS-13); 3. Recordkeeping, reporting, chemical inventory, and development of new information (page CRS-15); 4. Confidential treatment and public disclosure of information (page CRS-20); 5. Addressing risks of existing chemical substances and mixtures (page CRS-28); 6. Addressing risks of new chemical substances and significant new uses of chemical substances (page CRS-36); 7. Judicial review and enforcement (page CRS-39); 8. Relationship to state law (page CRS-42); 9. Resources to implement TSCA (page CRS-47); and 10. Other provisions (page CRS-49). 

Summary: This report compares H.R. 2576, the TSCA Modernization Act of 2015, as passed by the House on June 23, 2015, and the Senate's substitute amendment (S.Amdt. 2932) to H.R. 2576, the Frank R. Lautenberg Chemical Safety for the 21st Century Act, as passed by the Senate on December 17, 2015. The Senate amendment is based, in part, on S. 697, as reported by the Senate Committee on Environment and Public Works on April 28, 2015. The House bill and the Senate amendment would amend Title I of the Toxic Substances Control Act (TSCA). Enacted in 1976, TSCA is the primary federal law that authorizes the regulation of commercial chemicals throughout their lifecycle from manufacture to disposal. TSCA authorizes the Environmental Protection Agency (EPA) to determine whether regulation of a chemical is necessary to provide protection against "unreasonable risk of injury to health or the environment." The Senate amendment, but not the House bill, would also amend the Mercury Export Ban Act of 2008 and add a provision to the Public Health Service Act regarding potential cancer clusters. Over the 39-year history of TSCA, EPA, regulated entities, environmental and public health groups and others have observed significant challenges in implementing the statute. For example, concerns have been raised on whether the threshold to regulate a chemical under TSCA is too difficult for EPA to demonstrate and whether the agency is unnecessarily constrained by the requirement that it impose the "least burdensome requirement" to restrict a chemical. In addition, EPA has argued that limits in requesting test information have constrained its ability to assess risks of certain chemicals. Many have argued that these concerns have diminished public confidence in the "safety" of chemicals in commerce. Additionally, regulated entities and right-to-know advocates have raised concerns about the appropriate balance between disclosures of chemical information and confidentiality of business information submitted to EPA under TSCA. Regulated entities have also raised concerns that state and local governments are adopting different requirements with respect to particular chemicals and compliance may be difficult with this growing "patchwork" of requirements. They argue that there should be uniform regulation under TSCA nationally. However, certain states and others have expressed concerns regarding the role of preemption in limiting states' ability to regulate chemicals. Since 2005, these concerns and others led to the introduction of legislation that would amend TSCA in each Congress. The first section of the report provides a brief background on TSCA. The second section provides a brief comparison between the House bill and the Senate amendment and also provides a background discussion of seven issues: Prioritization of chemicals for the evaluation of risks; Regulatory threshold for restricting a chemical; Regulatory options for restricting a chemical; Requirements for the development of test information; Preemption of state requirements; Confidentiality and disclosures of information; and Resources to administer TSCA. Finally, Table 1 presents a side-by-side comparison of the provisions of existing law, the House bill, and the Senate amendment. This report does not provide a comprehensive analysis of the potential effect of particular provisions. Ultimately, the outcome, if either the House bill or the Senate amendment were enacted, depends on implementation.