Genetically Engineered Mosquito Experiment in California’s Central Valley Halted

In a victory for environmentalists, scientists and vulnerable agricultural communities across California, the California Department of Pesticide Regulation (DPR) announced yesterday the withdrawal of a permit for a mass release of experimental genetically engineered mosquitoes in the Central Valley.

The withdrawal of the biotech corporation Oxitec’s request halts the controversial proposed release of billions of genetically engineered insects. Scientists and other experts in the field have raised concerns about Oxitec’s proposal to release genetically engineered mosquitoes due to inadequate scientific review and lack of appropriate and relevant regulations, pressuring the company to disclose data critical to assessing potential public health and environmental impacts.

Oxitec applied in April 2022 for a research authorization permit to release genetically engineered mosquitoes in Tulare County. In separate letters to DPR earlier this year, scientists and legislators urged DPR to deny the Oxitec permit because of concerns about risks posed to human health, wildlife and vulnerable ecosystems, and the lack of regulations to control billions of genetically engineered mosquitoes released into an open-air environment.

“The withdrawal of Oxitec’s application is a victory for California residents and wild species,” said Rebecca Spector, west coast director at Center for Food Safety. “This withdrawal is in line with leaders from our state legislature who demanded a more comprehensive review of the impacts of these genetically engineered mosquitoes before the approval of this permit.”

Earlier this year, Assemblymember Laura Friedman (D-Glendale) stated in her office’s press release that “there are too many unknown factors when it comes to how (GE mosquitoes) could affect our biodiversity in the long run, including how this might influence populations of birds, bats, fish species, and other insects.”

“All Californians should be relieved that this permit has been withdrawn for the foreseeable future,” said Dana Perls, senior program manager at Friends of the Earth. “Significant scientific research on genetically engineered mosquitoes is still needed to understand the potential public health and environmental threats associated with the release of this novel genetically engineered insect.”

“This is a significant opportunity for California’s agricultural officials to hit pause and craft meaningful regulations that fully comply with the California Environmental Quality Act (CEQA). We must regulate not just this proposal for genetically engineered mosquitoes, but any proposal to release a genetically engineered animal in our state,” said Nan Wishner, founding board member of the California Environmental Health Initiative. “A full CEQA analysis requires thorough exploration of environmental harm and identification of less potentially harmful alternatives.”

"Genetically engineered mosquitoes are an environmental justice issue for Tulare County residents who should not be human experiments," said Angel Garcia, co-director of the statewide coalition Californians for Pesticide Reform and Tulare County resident. "We are already impacted by some of the worst pollution problems in the state and deserve prior informed consent to being part of an open-air biopesticide experiment. Ahead of any future proposal for genetically engineered insects, DPR needs to have robust regulations in place that protect community members, and meaningful, inclusive public participation in any decision making."

Before an unregistered pesticide can be field tested in the state, U.S. EPA would need to approve an experimental use permit ahead of any field release, and DPR would need to approve a research authorization application. With the withdrawal of the Oxitec application, there is no pending research authorization for the study of genetically engineered mosquitoes in California.