Colorado state regulators on Wednesday approved a preliminary plan to authorize more than 150 new oil and gas wells east of Aurora, clearing the way for a project that opponents fear could contaminate a local drinking water reservoir and further worsen air quality in the Front Range region.

The Colorado State Energy and Carbon Management Commissions have approved the Lowry Ranch Comprehensive Area Plan by a vote of 3 to 1. The plan was proposed by Crestone, a subsidiary of Denver-based Civitas Resources, and calls for the development of up to 11 drilling sites across 32,000 acres in Arapahoe County.

“Without a doubt, it is the wrong decision for the health, safety and environment of our community,” said Marsha Goldsmith Kamin, president of Save The Aurora Reservoir, a local advocacy group fighting the project.

But state regulators have allowed the project to move forward only if the company uses electric drilling rigs and equipment at all planned drilling sites. Huge gasoline- and diesel-powered engines have long been the standard power source for drilling and fracking operations. By requiring the switch to electricity, state regulators hope to reduce noise and prevent new sources of smog-forming pollution along Colorado’s Front Range, which has failed to meet federal air quality standards for more than two decades.

The proposed project is also a key test of Colorado’s recently overhauled oil and gas regulatory process. After years of bitter disputes over drilling and fracking, a 2019 law signed by Gov. Jared Polis gave local communities more control over new drilling and required state regulators to consider the broad public health and environmental impacts of development proposals.

A first step under the revised system requires project developers to submit comprehensive area plans (CAPs) to state regulators. By approving Civitas’ plan, Colorado has cleared the way for oil and gas development across the region for the next six years. However, the company still needs to get approval from the state and Arapahoe County for each drilling site.

Fossil fuel development could usher in a new chapter for an area that borders Metro Denver’s most remote residential areas. After serving as a military firing range and hosting four intercontinental ballistic missiles, the Colorado State Land Board purchased the prairie acreage from the federal government in the 1960s. Today, it borders a former landfill designated as a Superfund site and the Aurora Reservoir, a popular recreation area and important water source for the city of Aurora and its growing residential areas.

Local residents are concerned that fracking projects could disturb the Superfund site and contaminate water resources. In response, Civitas has agreed not to drill horizontal wells beneath the landfill.

While Kamin is glad that regulators will require all-electric equipment, he says regulators have not adequately addressed water quality concerns. Congressman Jason Crow, who represents Aurora, has also asked the U.S. Environmental Protection Agency whether it is investigating whether fracking could increase the risk of pollution contained in the landfill reaching the reservoir.

“We are not giving up. We will continue to take care of each and every one of these wells, especially the drilling platforms closest to the community,” Kamin said.

Local activists have received support from major environmental groups. Following the approval, Sierra Club executive director Ben Jealous released a statement saying his organization was “disappointed that Colorado regulators are siding with a billion-dollar corporation and abandoning residents who depend on a clean, protected Aurora Reservoir.”

Meanwhile, Kait Schwartz, director of the American Petroleum Institute, said the approval shows that Colorado remains “open for business” despite its recent push for stricter regulations on the oil and gas industry.

“This application and decision should serve as a model for how we handle future projects, and we look forward to continuing to work with state agencies, stakeholders and the public to ensure we act responsibly and meet our state’s increasingly demanding standards,” Schwartz said in a statement.