Title page 1

Contents 6

Introduction 9

1. Background 12

1.1. Why develop new technologies to remediate waste? 12

1.2. Considerations for containment versus environmental release 13

1.3. Role of federal agencies 15

2. Benefits, Limitations, Potential Risks, and Status of Engineered Microbes for Cleanup 18

2.1. Engineered microbes may offer benefits over existing remediation and waste treatment 18

2.2. Limitations and potential risks may restrict use or be difficult to address 19

2.2.1. Technical limitations 19

2.2.2. Potential risks 19

2.3. Engineered microbes for waste cleanup are not commercially available 20

3. Demonstrating Safety and Effectiveness 24

3.1. Gaps in knowledge 24

3.2. Insufficient testing infrastructure and standards 25

3.3. Regulatory burdens 29

4. Developing a Market 32

4.1. Unclear regulatory responsibilities and long review times 32

4.2. Lack of manufacturing facilities and demonstrations at scale 34

4.3. Public skepticism and a lack of community engagement 35

5. Alternatives to Policies Advancing Engineered Microbes for Cleanup 38

5.1. Contained approaches may address some, but not all concerns about testing for environmental release 38

5.2. The private market may address some, but not all challenges 38

5.3. Alternative policy options 39

6. Agency and Expert Comments 40

Appendix I. Objectives, Scope, and Methodology 41

Appendix II. Expert Participation 44

Appendix III. GAO Contacts and Staff Acknowledgments 46

Table 1. Key federal agencies involved in research and regulation relevant to engineered microbes for waste cleanup 15

Table 2. Policy option for gaps in knowledge 25

Table 3. Policy options to improve testing infrastructure and standards 28

Table 4. Policy option for regulations 31

Table 5. Policy options for unclear regulatory responsibilities and long review times 33

Table 6. Policy option for lack of manufacturing facilities and demonstrations at scale 35

Table 7. Policy options for public skepticism and a lack of community engagement 37

Table 8. Alternative policy options 39

Figure 1. Example areas where engineered microbes could be deployed for waste cleanup 10

Figure 2. Engineered microbes may be designed for contained use or environmental release 14

Figure 3. History of the coordinated framework for the regulation of biotechnology 17

Figure 4. Scaling up testing of engineered microbes for bioremediation 27