In 1976, President Gerald R. Ford signed the Toxic Substances Control Act (15 U.S.C. 2601 et seq . ; TSCA), giving the U.S. Environmental Protection Agency (EPA) authority to regulate production and use of industrial chemicals not otherwise regulated in U.S. commerce. Thirty-five years of experience with TSCA implementation and enforcement have demonstrated the strengths and weaknesses of the law and led many to propose legislative changes to TSCA's core provisions in Title I. Based on hearing testimony, stakeholders generally agree that TSCA needs to be updated, although there is disagreement about the extent and nature of any proposed revisions. Democrats introduced legislation to amend TSCA Title I in the 111 th Congress ( S. 3209 and H.R. 5820 ), but Congress did not vote on either bill. Those previous bills proposed generally similar changes to TSCA that were summarized in CRS Report R41335, Proposed Amendments to the Toxic Substances Control Act (TSCA): Senate and House Bills Compared with Current Law . On April 14, 2011, Senator Frank Lautenberg introduced similar, but not identical, legislation ( S. 847 ) in the 112 th Congress. To date, no other legislation has been introduced that would amend core provisions of TSCA Title I. Therefore, this report compares key provisions of S. 847 , as introduced, with provisions of TSCA Title I (15 U.S.C. 2601 et seq. ) that would be affected if S. 847 becomes law. These provisions are summarized in Tables 1 through 5. New provisions that would be added to the end of TSCA Title I by S. 847 —for example, those related to reduced use of animals for toxicity testing—are summarized in Table 6 . S. 847 would not affect Titles II through VI of TSCA, nor would it change the basic organization of TSCA Title I. For example, provisions related to testing would still be in Section 4, requirements for notifying EPA when a new chemical or new use is proposed would still be in Section 5, and regulatory authorities would remain in Section 6. Also unaffected would be changes to TSCA Title I that were enacted during the 110 th Congress, such as a provision that bans exports of elemental mercury. However, S. 847 would amend or delete most of the original Title I provisions and would make substantial additions to current law. Some key changes are summarized below. S. 847 , as introduced, directs the EPA Administrator to establish varied or tiered minimum data set requirements for different chemical substances or categories of substances. Manufacturers would be given a specified period of time to produce and submit data meeting the minimum data requirements for chemicals that are already in commerce and for any new chemicals that they propose to manufacture. Data sets would have to be submitted within five years of the date of enactment of S. 847 . Current law does not routinely require submission of data for chemicals, but EPA has the authority to require data submission if it promulgates a rule based on a finding that a chemical "may present an unreasonable risk of injury to health or the environment" and the agency demonstrates a data need. S. 847 directs the EPA Administrator to prioritize all chemicals already in commerce for evaluation and risk management by establishing a list that "contains the names of the chemical substances that … warrant placement within 1 of 3 priority classes … and identifies the priority class to which each listed chemical substance or category of chemical substance has been assigned by the Administrator." Priority class 1 chemicals would be defined as those "... that the Administrator determines require immediate risk management." The Administrator would be required to place between 20 and 30 chemicals in this category, and the data set for a high-priority chemical would have to be submitted within 18 months of its placement on the priority class 1 list. Priority class 2 chemicals would be defined as those "that the Administrator determines require safety standard determinations … based on any more-than-theoretical concern, that there is uncertainty as to whether a chemical substance would satisfy the safety standard." Priority class 3 chemicals would be defined as those "that the Administrator determines require no immediate action." Chemicals are not prioritized under current law. The Senate bill would establish a health-based safety standard for chemical use that protects vulnerable populations: manufacturers would be required to produce scientific data demonstrating "there is a reasonable certainty that no harm will result to human health or the environment from aggregate exposure to the chemical substance." S. 847 would prohibit manufacture, processing, and distribution of any chemical substance for any use that had not been included in the safety determination issued for that chemical. Moreover, an exemption from a prohibition would be allowed for a particular use only if: it were "in the paramount interest of national security"; lack of the chemical use "would cause significant disruption in the national economy"; the use were essential or critical and there were no safer feasible alternative; or the chemical use, relative to alternatives, provided a benefit to health, the environment, or public safety. In contrast, current law allows manufacture of and commerce in a chemical unless EPA promulgates a rule including a finding that a chemical presents or will present an "unreasonable risk" to human health or the environment. If EPA demonstrates that a risk associated with a chemical is unreasonable (relative to the benefits provided by the chemical and the estimated risks and benefits of any alternatives), the Agency is required to regulate, but only to the extent necessary to reduce that risk to a reasonable level and using "the least burdensome" restriction. S. 847 would expedite regulatory action, relative to the process under current law, by authorizing EPA in some cases to issue administrative orders instead of rules (which must be promulgated under current law), exempting certain EPA decisions from judicial review, and removing certain TSCA requirements that are in addition to requirements specified in the Administrative Procedure Act (5 U.S.C. 553) for notice and comment rulemaking. The scope of EPA oversight also would be expanded by S. 847 . As introduced, the bill includes language that allows EPA to define various distinct forms of substances that are the same in terms of molecular identity but differ in structure and function, such as manufactured nanoscale forms of carbon and silver. The introduced bill also broadens the scope of environmental risks that EPA may manage to include risks found in the indoor environment; currently, TSCA applies only to chemicals in the ambient environment. S. 847 also would appear to more clearly authorize EPA control of risks posed by articles containing a substance. The proposed amendments to TSCA would increase public access to information about EPA's decisions, as well as to some information about chemicals that currently is treated as confidential business information. S. 847 would authorize EPA activities not currently authorized under TSCA to allow implementation of three international agreements pertaining to persistent organic pollutants and other hazardous chemicals. For example, the proposal would authorize EPA to regulate chemicals manufactured solely for export. The authority provided by the bill would be specific to three international agreements, rather than more generally authorizing regulatory activity to implement any ratified international agreement concerning chemicals. The bill would prohibit production and use of chemicals when it was inconsistent with U.S. obligations under any of the three international agreements after they had entered into force for the United States. For more information about these agreements, see CRS Report RS22379, Persistent Organic Pollutants (POPs): Fact Sheet on Three International Agreements . The effect of TSCA on state and local chemical laws would be modified by S. 847 , as introduced. Current law, TSCA Section 18, generally does not preempt state laws. However, if EPA requires testing of a chemical under section 4, no state may require testing of the same substance for similar purposes. Similarly, if EPA prescribes a rule or order under section 5 or 6, no state or political subdivision may have a requirement for the same substance to protect against the same risk unless the state or local requirement is identical to the federal requirement, is adopted under authority of another federal law, or generally prohibits the use of the substance in the state or political subdivision. TSCA authorizes states and political subdivisions to petition EPA, and authorizes EPA to grant petitions, by rule, to exempt a law in effect in a state or political subdivision under certain circumstances. A petition may be granted if compliance with the requirement would not cause activities involving the substance to be in violation of the EPA requirement, and the state or local requirement provides a significantly higher degree of protection from the risk than the EPA requirement does, but does not "unduly burden interstate commerce." S. 847 would simplify this section of TSCA. An amended TSCA would not preempt laws relating to a chemical substance, mixture, or article unless compliance with both federal and the state or local law were impossible. Several new provisions are included in S. 847 . One provision, for example, would require definition and listing of localities with populations that are "disproportionately exposed" to toxic chemicals. EPA would be directed to develop an action plan to reduce exposure in such "hot spots." EPA would be required to establish a program to create market incentives for the development of safer alternatives to existing chemical substances that reduce or avoid the use and generation of hazardous substances. The program would be required to expedite review of a new chemical substance if an alternatives analysis indicated it was a safer alternative, and to recognize a substance or product determined by EPA to be a safer alternative. Another provision would direct the EPA Administrator to coordinate with the Secretary of Health and Human Services to conduct a biomonitoring study to determine whether a chemical that research had indicated may be present in human biological substances and that may have adverse effects on human development in fact was present in pregnant women and infants.