BENSON, Ariz.— The Center for Biological Diversity and Health Over Wealth Benson are urging the U.S. Environmental Protection Agency to reject an air pollution permit for a proposed aluminum plant in Benson, Arizona. The plant would emit pollution that could harm nearby communities and the San Pedro River.

“If this plant is built it’ll release toxic air pollution that could harm wildlife and people living nearby. That’s an unfair price to pay, especially with the San Pedro River right next door,” said Russ McSpadden, a Southwest conservation advocate at the Center for Biological Diversity. “The river is home to a rich array of animals, including the threatened yellow-billed cuckoo, and they could all be at risk. The EPA must step in and protect this unique ecosystem and the people who live nearby.”

The legal filing by the Center for Biological Diversity, supported by Health Over Wealth Benson, calls on the EPA to reject the Arizona Department of Environmental Quality permit allowing Aluminum Dynamics to build and operate the aluminum ingot casting plant.

The petition says that Arizona’s issuance of the plant’s air permit violates the Clean Air Act by failing to adequately monitor air pollution and failing to ensure compliance with toxic air pollution limits.

“This air permit allows dangerous pollution, including fine particulates and toxic heavy metals, into the air Benson families breathe every day,” said Misty Bloom, co-founder of Health Over Wealth Benson. “State regulators approved a permit that ignores real risks from pollutants like lead, dioxins and acid gases that can travel beyond the site and into our homes, schools and lungs. Our community has been clear: this permit puts public health on the line, and the EPA must reject it before that harm becomes reality.”

Air pollution, water use for cooling, and other harms from the plant have drawn fierce local opposition. Despite that, the state approved Aluminum Dynamic’s air pollution permit in February over objections from Benson residents.

In August 2025 the nonprofit Health Over Wealth Benson and two Benson residents sued the city of Benson and Aluminum Dynamics over alleged zoning code violations.

That same month the Center and the San Pedro 100 sued the Arizona Department of Water Resources, seeking review of whether groundwater supplies for a nearby development and the aluminum plant are legally and physically available.

This groundwater is critical to the San Pedro River, which provides habitat for millions of migratory songbirds and many endangered species. Studies show additional groundwater pumping would violate federal reserved water rights for the San Pedro Riparian National Conservation Area.