TSCA provides EPA with the authority, upon making certain determinations, 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. Of the over 83,000 chemicals currently in the TSCA inventory, about 62,000 were already in commerce when EPA began reviewing chemicals in 1979. Since then, over 21,000 new chemicals—about 700 each year, on average—have been added to the inventory and are now in use as existing chemicals. To assess a chemical’s risks, EPA examines its toxicity or potential adverse effects and the amount of human and environmental exposures. TSCA generally requires the industry to notify EPA at least 90 days before producing or importing a new chemical. These notices are to contain such information as the chemical’s molecular structure and intended uses, which EPA uses to evaluate the chemical’s potential risks. TSCA also authorizes EPA to promulgate rules to require manufacturers to perform tests on chemicals in certain circumstances or to provide other data, such as production volumes, on existing chemicals. In addition, TSCA requires chemical companies to report to EPA any data that reasonably support a conclusion that a chemical presents a substantial risk. If EPA finds that a chemical’s risks are unreasonable, it can prohibit or limit the chemical’s production, processing, distribution, use, and disposal or take other action, such as requiring warning labels on the substance. While TSCA authorizes EPA to release some chemical information obtained by the agency under the act, it allows chemical companies to claim certain information, such as data disclosing chemical processes, as confidential business information. EPA generally must not disclose such information unless such disclosure is necessary to protect against an unreasonable risk of injury to health or the environment. Evaluating the appropriateness of confidentiality claims is time- and resource-intensive, and EPA does not challenge most claims. State environmental agencies and others have expressed interest in obtaining information claimed as confidential business information for use in various activities, such as developing contingency plans to alert emergency response personnel to the presence of highly toxic substances at manufacturing facilities. In previous reports, we have identified options for statutory changes to improve EPA’s ability to make more chemical information publicly available. IRIS was created in 1985 to help EPA develop consensus opinions within the agency about the health effects from chronic exposure to chemicals. Its importance has increased over time. EPA, state and local environmental programs, international regulatory bodies, academia, industry, and others now rely heavily on the IRIS database to support risk- based decision making to protect public health and the environment. A typical IRIS assessment contains a qualitative description of the hazard posed by a chemical and a quantitative assessment of the relationship between exposure and the likelihood and severity of adverse health effects. The focus of IRIS toxicity assessments is on the potential health effects of long-term (chronic) exposure to chemicals. According to the Office of Management and Budget (OMB), EPA is the only federal agency that develops qualitative and quantitative assessments of both cancer and noncancer risks of exposure to chemicals, and EPA does so largely under the IRIS program. The quantitative estimates of potency that EPA provides are particularly important, as they are required to conduct quantitative risk assessments. EPA uses risk assessments developed with IRIS toxicity data to determine whether the identified health risks warrant regulatory or other actions. Examples of subsequent decisions that could stem from a determination that action is necessary to protect public health include how much of a chemical a company may discharge into a river, which substances may be stored at a hazardous waste facility, the extent to which a hazardous waste site must be cleaned up, levels for air emissions, and allowable levels of contamination in drinking water. EPA lacks adequate scientific information on the toxicity of many chemicals that are or may be found in the environment. For existing chemicals, TSCA generally places the burden of obtaining data on EPA, rather than on the companies that produce the chemicals. This approach requires that EPA demonstrate certain health or environmental risks before it can require companies to further test their chemicals. As a result, EPA has only limited information on the health and environmental risks posed by these chemicals. Furthermore, while TSCA authorizes EPA to review existing chemicals, it generally provides no specific requirement, time frame, or methodology for doing so. Significantly, chemical companies are not required to develop and submit toxicity information to EPA on existing chemicals unless the agency finds that a chemical may present an unreasonable risk of injury to human health or the environment or 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 the environment in substantial quantities. EPA must also determine there are insufficient data on a chemical to reasonably determine its effects on health or the environment and that testing is necessary to develop such data before the agency can require a company to test its chemicals for harmful effects. This structure places the burden on EPA to demonstrate a need for data on a chemical’s toxicity rather than on a company to demonstrate that a chemical is safe. As a result, EPA does not routinely assess the risks of the more than 83,000 commercial chemicals in use. As we have previously reported, TSCA’s chemical review provisions could be strengthened by requiring EPA’s systematic review of existing chemicals. TSCA could be amended to establish a time frame for the review of existing chemicals, putting existing chemicals on a more equal footing with new chemicals. However, because of the large number of existing chemicals, EPA would need the flexibility to identify which chemicals should be given priority. TSCA could be amended to require individual chemical companies or the industry as a whole to compile and submit chemical data as a condition of manufacture or import above some specified volume or other criteria. Regarding new chemicals, TSCA generally requires chemical companies t submit a premanufacture notice to EPA before they manufacture or impo new chemicals and to provide any available test data. Yet EPA estimates that most premanufacture notices do not include any test data, and onlyabout 15 percent include health or safety test data. These tests may takeover a year to complete and cost hundreds of thousands of dollars, and chemical companies usually do not perform them voluntarily. Because EPA generally does not have sufficient data on a chemical’s properties an effects when reviewing a new chemical, EPA uses models to compare new chemicals with chemicals that have similar molecular structures and for which test data on health and environmental effects are available, which can take years. Furthermore, EPA bases its exposure estimates for new chemicals on information contained in premanufacture notices— information that chemical companies generally are not bound by and that may change without notice. For example, companies m production levels or expand the uses of a chemical, potentially increasing the risk of injury to human health or the environment. An option that we have previously reported could make TSCA more effective and provide EPA with adequate information on chemicals is revising the act to require companies to test their chemicals and submit the results to EPA with their premanufacture notices. Currently, s uch a step is required only if EPA makes the necessary findings and promul a testing rule. A major drawback to testing is its cost to chemical companies, which may reduce their willingness to perform chemical research and invest in innovation. To reduce such costs or to delay them until production is sufficient to offset them, requirements for testing could be based on production volume. For example, in Canada and the European Union, testing requirements for low-volume chemicals are less extens and complex than for high-volume chemicals. We previously rep Congress could give EPA, in addition to its current authorities under section 4 of TSCA, the authority to require chemical substanc manufacturers and processors to develop test data based on, for example, substantial production volume and the necessity for testing. Another option we reported was to provide EPA with greater authority to require additional testing in areas where EPA’s analysis models do not adequately predict toxicity. Under such an option, EPA cou minimal set of tests for new chemicals to be submitted with premanufacture notices. Additional and more complex and costly testing could be required as a new chemical’s potential risks increase, based on , for example, production or environmental release levels. According to some chemical companies, the cost of initial testing could be reduced by hey are amending TSCA to require EPA to review new chemicals before t marketed, rather than before they are manufactured. This could substantially reduce the expense of testing because, according to EP about half of the premanufacture notices the agency receives from chemical companies are enter the marketplace. for new chemicals that, for various reasons, never In addition to TSCA, EPA assesses chemicals under its IRIS program reported in March 2008 that this key program was at serious risk of becoming obsolete because the agency has not been able to keep its existing assessments current; decrease its backlog of 70 assessments complete assessments of key chemicals of concern, such as dioxin, formaldehyde, and trichloroethylene (TCE). Among other things, we found that EPA’s efforts to finalize IRIS assessments were impeded by a combination of factors, including OMB’s requiring two additional reviews of IRIS assessments by OMB and other federal agencies with an interest i the assessments, such as the Department of Defense. Moreover, the two interagency reviews involved other federal agencies in EPA’s IRIS assessment process in a manner that hindered EPA’s ability to manage its assessments and limited their credibility and transparency. For example, the input these agencies provided to EPA was treated as “deliberative” a was not released to the public. As a result, we recommended that EPA adopt a streamlined, more transparent assessment process. A revised process that EPA subsequently adopted in 2008 did not incorporate our recommendations and actually exacerbated the concerns we identifi ed about productivity and credibility. As a result, we included the IRIS program along with TSCA in our high-risk designation on assessing and controlling toxic chemicals.