Federal laws have been enacted over the years to determine the health and environmental hazards associated with toxic chemicals and to address these problems. Even with the existence of media-specific environmental laws enacted in the early 1970s, such as the Clean Air Act and the Clean Water Act, problems with toxic chemicals continued to occur. In addition, Congress became increasingly concerned about the long-term effects of substantial amounts of chemicals entering the environment. TSCA was enacted to authorize EPA to collect information about the hazards posed by chemical substances and to take action to control unreasonable risks by either preventing dangerous chemicals from making their way into use or placing restrictions on those already in commerce. Under the act, EPA can control the entire life cycle of chemicals from their production, distribution in commerce, and use to their disposal. Other environmental and occupational health laws generally control only disposal or release to the environment, or exposures in the workplace. The scope of TSCA includes those chemicals manufactured, imported, processed, distributed in commerce, used, or disposed of in the United States but excludes certain substances regulated under other laws. TSCA also specifies when EPA may publicly disclose chemical information it obtains from chemical companies and provides that chemical companies can claim certain information, such as data disclosing chemical processes, as confidential business information. EPA’s authority to ensure that chemicals in commerce do not present an unreasonable risk of injury to health or the environment is established in five major sections of TSCA. The purpose and application of these sections are shown in table 1 and described in further detail below. Under the provisions for chemical testing in section 4 of TSCA, EPA can promulgate rules to require chemical companies to test potentially harmful chemicals for their health and environmental effects. However, EPA must first determine that testing is warranted based on some toxicity or exposure information. Specifically, to require such testing, EPA must find that a chemical (1) may present an unreasonable risk of injury to human health or the environment or (2) is or will be produced in substantial quantities and that either (a) there is or may be significant or substantial human exposure to the chemical or (b) the chemical enters or may reasonably be anticipated to enter the environment in substantial quantities. EPA must also determine that there are insufficient data to reasonably determine or predict the effects of the chemical on health or the environment and that testing is necessary to develop such data. Under the provisions for new chemical review and significant new use rules in section 5 of TSCA, chemical companies are to notify EPA at least 90 days before beginning to manufacture a new chemical (premanufacture notice review). Section 5 also allows EPA to promulgate significant new use rules, which require companies to notify EPA at least 90 days before beginning to manufacture a chemical for certain new uses or in certain new ways (significant new use notice review). Such rules require existing chemicals to undergo the same type of review that new chemicals undergo. For example, EPA may issue a significant new use rule if it learns that a chemical that has previously been processed as a liquid is now being processed as a powder, which may change how workers are exposed to the chemical. Section 5 of the act also authorizes EPA to maintain a list of chemicals—called the chemicals of concern list—that present or may present an unreasonable risk of injury to health or the environment. Under the provisions for chemical regulation in section 6 of TSCA, EPA is to apply regulatory requirements to chemicals for which EPA finds a reasonable basis exists to conclude that the chemical presents or will present an unreasonable risk of injury to health or the environment. To adequately protect against a chemical’s risk, EPA can promulgate a rule that bans or restricts the chemical’s production, processing, distribution in commerce, disposal, or use or requires warning labels be placed on the chemical. Under TSCA, EPA must choose the least burdensome requirement that will adequately protect against the risk. Under the provisions for industry reporting of chemical data in section 8(a), EPA is to promulgate rules under which chemical companies must maintain records and submit such information as the EPA Administrator reasonably requires. This information can include, among other things, chemical identity, categories of use, production levels, by-products, existing data on adverse human health and environmental effects, and the number of workers exposed to the chemical, to the extent such information is known or reasonably ascertainable. Under section 8(a), EPA issues rules to update the TSCA inventory. For example, in August 2011, EPA finalized its TSCA Chemical Data Reporting rule (previously referred to as the Inventory Update Reporting Modifications Rule); the rule requires companies to report, among other things, exposure-related information, such as production volume and use data, on chemicals manufactured or imported over a certain volume per year. In addition, section 8(d) provides EPA with the authority to promulgate rules under which chemical companies are required to submit lists or copies of existing health and safety studies to EPA. Section 8(e) generally requires chemical companies to report any information to EPA that reasonably supports a conclusion that a chemical presents a substantial risk of injury to health or the environment. Under the provisions for disclosure of chemical data in section 14, EPA may disclose chemical information it obtains under TSCA under certain conditions. Chemical companies can claim certain information, such as data disclosing chemical processes, as confidential business information. EPA generally must protect confidential business information against public disclosure unless necessary to protect against an unreasonable risk of injury to health or the environment. Other federal agencies and federal contractors can obtain access to this confidential business information to carry out their responsibilities. EPA may also disclose certain data from health and safety studies. We have previously reported that EPA has historically faced challenges implementing many of the provisions of TSCA, in particular (1) obtaining adequate information on chemical toxicity and exposure through testing provisions; (2) banning or limiting chemicals; and (3) disclosing chemical data and managing company assertions of confidentiality. EPA has found it difficult to obtain adequate information on chemical toxicity and exposure because TSCA does not require companies to provide this information and, instead, requires EPA to demonstrate that chemicals pose certain risks before it can ask for such information. Specifically, we reported in 2005 that under section 4—provisions for chemical testing—EPA has found its authority to be difficult, time- consuming, and costly to use. The structure of this section places the burden on EPA to demonstrate certain health or environmental risks before it can require companies to further test their chemicals. While TSCA authorizes EPA to review existing chemicals, it generally provides no specific requirement, time frame, or methodology for doing so. Instead, EPA conducts initial reviews after it receives information from the public or chemical companies that a chemical may pose a risk. As a result, EPA has only limited information on the health and environmental risks posed by these chemicals. In our June 2005 report, we suggested that Congress consider amending TSCA to provide explicit authority for EPA to enter into enforceable consent agreements under which chemical companies are required to conduct testing, and give EPA, in addition to its current authorities under section 4 of TSCA, the authority to require chemical substance manufacturers and processors to develop test data based on substantial production volume and the necessity for testing. In addition, we reported in June 2005 that under section 5—provisions for new chemical review—TSCA generally requires chemical companies to submit a notice to EPA (known as a “premanufacture notice”) before they manufacture or import new chemicals and to provide any available test data. EPA estimated that most notices do not include any test data and that about 15 percent of them included health or safety test data. These tests may take over a year to complete and cost hundreds of thousands of dollars, and chemical companies usually do not perform them voluntarily. However, chemical companies are not generally required under TSCA to limit the production of a chemical or its uses to those specified in the premanufacture notice or to submit another premanufacture notice if changes occur. For example, companies may increase production levels or expand the uses of a chemical, potentially increasing the risk of injury to human health or the environment. EPA has had difficulty demonstrating that chemicals should be banned or have limits placed on their production or use under section 6—provisions for controlling chemicals. Specifically, we reported, in June 2005, that since Congress enacted TSCA in 1976, EPA has issued regulations under section 6 to ban or limit the production or restrict the use of five existing chemicals or chemical classes out of tens of thousands of chemicals listed for commercial use on the agency’s TSCA inventory. EPA’s 1989 asbestos rule illustrates the difficulties EPA has had in issuing regulations to control existing chemicals. In 1979, EPA started considering rulemaking on asbestos. After concluding that asbestos was a potential carcinogen at all levels of exposure, EPA promulgated a rule in 1989 prohibiting the future manufacture, importation, processing, and distribution of asbestos in almost all products. Some manufacturers of asbestos products filed suit against EPA, arguing, in part, that the rule was not promulgated on the basis of substantial evidence regarding unreasonable risk. In 1991, the Fifth Circuit Court of Appeals ruled for the manufacturers and returned parts of the rule to EPA for reconsideration. In reaching this conclusion, the court found that EPA did not consider all necessary evidence and failed to show that the control action it chose was the least burdensome reasonable regulation required to adequately protect human health or the environment. Since the court’s 1989 decision, EPA has only exercised its authority to ban or limit the production or use of an existing chemical once—for hexavalent chromium, a known human carcinogen widely used in industrial cooling towers—in 1990. EPA has limited ability to publicly share the information it receives from chemical companies under TSCA. Specifically, as we reported in 2005, EPA has not routinely challenged companies’ assertions that the chemical data they disclose to EPA under section 14—disclosure of chemical data—are confidential business information, citing resource constraints.