"Background: Engineered microbes are microorganisms (like bacteria and fungi) that have been genetically modified for a specific purpose. These organisms may help address cleanup and remediation of various substances, including heavy metals and plastics. An estimated 11 million metric tons of plastic enter the oceans each year and microplastics are estimated to persist in the environment for centuries. Plastic and other pollutants in the U.S. can contaminate air and water resources which may have a significant economic impact on food production (including farming and fishing), sports, recreation, and tourism. This technology assessment will explore advances in bioengineering that may enable clean-up and remediation, including potential benefits, challenges, and--if applicable--policy options. In 2023, GAO issued a Science & Tech spotlight (GAO-23-106648) which noted that scientists are exploring the use of bioengineered microorganisms to help reduce pollution. The Coordinated Framework for the Regulation of Biotechnology, established in 1986 and last updated in 2017, describes regulatory pathways for the use of bioengineered microbes within the Environmental Protection Agency, Food and Drug Administration, and U.S. Department of Agriculture--the three applicable regulatory agencies. Key Questions: 1) What microbial biotechnologies are available or in development for use in cleanup and remediation? 2) What are the potential benefits and challenges of developing and using these biotechnologies? 3) What options, if any, could policymakers consider to help enhance the opportunities or address the challenges associated with these biotechnologies?"