Plans for Colorado’s largest battery plant in Brighton nearly ran out of juice in the face of strong opposition from neighbors who fear chemical contamination and fires from the planned lithium-ion manufacturing facility.

But in a 4-3 vote Tuesday night, the Brighton City Council passed an ordinance granting the proper zoning for the site on East Bromley Lane. The approval will allow Amprius Technologies Inc. to build out a 775,000-square-foot facility within a long-vacant industrial building to produce batteries for a world rapidly turning to non-fossil fuel energy sources.

The vote followed several hours of testimony and fraught public input at the well-attended meeting. A steady stream of neighbors told the council that the site, at 18875 East Bromley Lane, was too close to hundreds of homes and that the risk of exposure to chemical releases or fires at the plant was too great.

“I don’t have anything against the company, I just have a problem with where you want to put it,” said Denise Swetkovich, who lives just north of the site. “It’s right in the middle of all the houses. It would be great to have this company here, in another space.”

She cited lithium and other chemicals used in the manufacture of industrial batteries as a big concern for her and her neighbors.

“Hazardous materials in a community — that’s just not a good fit at all,” Swetkovich said.

Another nearby homeowner, Jessie Williams, said the presence of Amprius’ plant could impact home values and increase homeowners insurance rates. And while the company promises to capture much of the emissions it produces, “the rest of it will be vented out to the rest of us.”

“That’s unfair,” she said.

Also in the audience Tuesday were a number of project supporters who touted the more than 300 jobs and the nearly $200 million investment the California-based company will bring to the Adams County city. The processes behind battery manufacturing have been proven safe, they said.

Amprius will fill the bulk of a 1.3 million-square-foot building that once served as a distribution center for Kmart and Sears but has been empty for years. Natalie Cummings, president and CEO of the Brighton Chamber of Commerce, said that means critical jobs for the northern suburb.

“The impact of those jobs, they will echo throughout the local economy,” she said. “This will lead to economic growth and the stimulation of our existing businesses. This ripple will cause existing businesses to thrive and will also potentially birth countless other businesses.”

When Amprius announced Brighton as its choice for a new gigawatt-scale factory in March, the company received praise from Gov. Jared Polis and U.S. Rep. Yadira Caraveo. Just a few weeks earlier, the company had received approval for up to $5.5 million in state job growth incentive tax credits from the Colorado Economic Development Commission.

But more than 500 homeowners and residents concerned about the potential impacts of a large industrial operation in their midst signed a petition opposing the rezoning that would allow Amprius to begin operations.

The opposition culminated in an Aug. 10 decision by the Brighton Planning Commission to recommend against the rezoning. A majority on the commission concluded it was not the right location for an operation using hazardous chemicals in its manufacturing process.

Amprius, founded in 2008, produces a silicon anode platform to use in battery cells. Silicon can store up to 10 times more lithium than graphite, which traditionally has been used. As a result, the batteries deliver up to 100% higher energy density than standard lithium-ion batteries, according to the company.

The company’s technology has been used in military drones, high-altitude pseudo-satellites and uncrewed aerial vehicles. Its growing production capacity will allow the company to expand into manufacturing electric vehicle batteries, Amprius says.

Councilman Peter Padilla said he trusted the city’s fire department in its determination that the plant wouldn’t pose an unreasonable danger to the community.

“We have a creative option in front of us that our professionals tell me has safety concerns in hand,” he said.

But Councilwoman Ann Taddeo, who along with colleagues Mary Ellen Pollack and Matt Johnston voted no, said the benefits of Amprius’ plant don’t outweigh the concerns.

“I don’t want the residents of this city to wonder if they’re going to be healthy, 10 years from now or 15 years from now,” she said.

Amprius is expected to begin work retrofitting the building later this year, with battery production slated to start in 2025.

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