Federal regulations, especially those addressing health, safety, and the environment, can generate hundreds of billions of dollars in benefits and costs to society annually. Various statutes, executive orders, and OMB guidance direct federal agencies to analyze the benefits and costs of proposed regulations. These analyses-known as RIAs-can also provide affected entities, agencies, Congress, and the public with important information about the potential effects of new regulations. According to OMB, EPA regulations account for the majority of the estimated benefits and costs of major federal regulations. GAO was asked to review EPA's RIAs for recent regulations. This report examines how EPA has used RIAs during the rulemaking process and the extent to which EPA adhered to OMB guidance on selected elements of RIAs for recent rules. GAO reviewed RIAs from a nonprobability sample of seven recent air, water, and other environmental regulations, assessed them against relevant OMB guidance, and interviewed agency officials.