An Act to Prohibit Geoengineering
LD499 would prohibit any person from engaging in, authorizing, or funding “geoengineering” in Maine, except for limited scientific research activities authorized by the Department of Environmental Protection. The bill defines geoengineering broadly as deliberate, large-scale intervention in the Earth’s natural systems to counteract climate change, and specifically includes carbon dioxide management, solar radiation management, stratospheric aerosol injection, and weather modification techniques such as cloud seeding.
The bill also creates a regulatory and enforcement framework for the Department of Environmental Protection. Authorized research would have to occur in a controlled environment, avoid weather modification and intentional release of substances or particles into the atmosphere or environment, and be accompanied by annual reporting on the activity, findings, and potential environmental effects. Violations would be treated as a Class E crime and carry a civil-style fine of $10,000 per day, with the bill expressly overriding other provisions of law that might otherwise limit enforcement.
If enacted, LD499 would add a new prohibition to Maine law restricting geoengineering-related activities and funding, while giving the Department of Environmental Protection authority to oversee and enforce the ban. It would affect researchers, private entities, and any person or organization involved in climate intervention, atmospheric experimentation, cloud seeding, or related funding streams, while carving out a narrow exception for department-authorized controlled research. The bill would also create new criminal liability and daily financial penalties for violations, making it a significant expansion of state oversight into climate intervention activities.
The available voting history suggests the bill faced substantial opposition. On April 29, 2025, the House recorded an 88-57 vote for an “Ought Not to Pass” report, indicating that a majority of members did not support advancing the measure. No committee transcript is available here, so the discussion record does not show detailed arguments, but the vote outcome indicates the bill was not broadly embraced.
The main point of contention is the scope of the prohibition. Supporters appear to view geoengineering as a risky form of climate manipulation that should be banned outright, while opponents likely object to the breadth of the definition, the inclusion of weather modification and carbon capture-related concepts, and the criminal penalties attached to violations. Another likely dispute is the research exception: the bill allows only tightly controlled, department-authorized scientific research, which may be seen as too restrictive by researchers and industry stakeholders. The strong “ought not to pass” vote suggests these concerns outweighed support for the proposal.