In 2023, a new study commissioned by the Sierra Club, “Coming Clean on Industrial Emissions: Challenges, Inequities, and Opportunities in U.S. Steel, Aluminum, Cement, and Metcoke,” provided an in-depth look at heavy manufacturing facilities around the country. At the heart of the report is a new database that examines domestic facilities in four heavy industries operating in 2020, including 7 facilities that produced primary aluminum. Of the seven facilities producing primary aluminum, two are located in Western Kentucky: the Century Sebree aluminum smelter in Robards, KY and the Century aluminum plant at Hawesville, KY (temporarily curtailed). Century Sebree in particular is the highest emitter of perfluorocarbons (PFCs) of any domestic aluminum facilities. The facility correspondingly has the worst Risk-Screening Environmental Indicators score among domestic aluminum facilities. Two additional aluminum smelting sites are adjacent to Kentucky in Marston, MO and Newburgh, IN, making the industrial pollution from the smelting process a concern for the entire region’s air and water quality.
Residents near the Century Sebree plant in Robards have known about poor air quality from the emission of PFCs during the smelting process at the aging facility for years, and Sierra Club members have been a part of the fight to get the industry to clean up its production.
Aluminum production in Kentucky: a vital industry that needs to clean up
By Nadia Steinzor, policy and research analyst, Environmental Integrity Project
Look around and you’ll see it everywhere. Appliances in the kitchen. Computers on desks. Cars in the driveway. A beverage can in your hand. Aluminum is central to our daily lives—and its popularity is only growing given the urgent need to shift to clean energy and transportation in the face of climate change.
Because aluminum is lightweight, durable, and highly recyclable, it’s a key ingredient in solar panels and wind turbines, more efficient cars and planes, and construction and packaging materials. Demand for the metal is set to skyrocket, bolstering the hopes of companies and policymakers for a U.S. industrial turnaround.
As aluminum gains the spotlight, the negative impacts of its production are also becoming more apparent. Much of the harm occurs in other countries, where the mining of bauxite ore (the rock containing aluminum as a mineral) and nearly all of the refining of bauxite into alumina powder occurs. But climate and air and water pollution from the next step in the production chain, the smelting of alumina into brand new metal, are experienced acutely closer to home—including in Kentucky.
Aluminum in the Commonwealth
After long being an aluminum powerhouse, the U.S. went through a major decline and today there are only six smelters left. Kentucky is home to two of them, both operated by Century Aluminum. The Hawesville smelter was built in 1969 along the Ohio River in Hawesville, and the Sebree smelter was built in 1972 near the Green River in Robards.
Kentucky smelters accounted for nearly 40 percent of new U.S. aluminum produced in 2022 (about 320,000 tons). Sebree has been operating close to its maximum capacity for the last several years and employs over 600 people. Century idled the Hawesville smelter in mid-2022, putting about 500 people out of work; it’s not clear when the plant will re-start.
Western Kentuckians may also be familiar with the Alcoa Warrick complex in Newburgh, Indiana, where the smelter and supporting power plant tower over the Ohio River. In addition, several Kentucky plants produce aluminum made from scrap and recycled metal. While this “secondary” production can harm local communities, they also use a fraction of the energy and generate far less pollution than smelters.
High energy use, dirty air
Smelting is very energy-intensive, requiring a continuous electric current that runs through giant production “pots.” Very high temperatures (up to 1800oF) are then needed to keep the metal in a molten state before it's cast into usable forms. In 2021, over 80 percent of the greenhouse gas emissions from the Hawesville and Sebree smelters was from the power supply. That year, each smelter consumed about three billion kilowatt-hours of energy, equivalent to the average electricity use of 270,000 U.S. homes.
Aluminum smelters also stand out among industrial polluters for their emissions of perfluorocarbons (PFCs). Compared to the climate impact of carbon dioxide over a 100-year period, PFC-14 is 6,600 times and PFC-116 is 11,000 times more powerful; both gases remain in the atmosphere for thousands of years. In 2021, PFCs accounted for more than half of Hawesville’s greenhouse gas emissions and a third of Sebree’s.
Smelters also pack a punch when it comes to local air quality. Key pollutants include sulfur dioxide (SO2) and particulate matter, which harm respiratory and cardiovascular health and fluorides that damage trees and crops.
The Hawesville smelter has violated air pollution limits in its permit at least a dozen times in the last few years, especially for particulates and fluorides. The Sebree smelter is a main reason why parts of Henderson County are violating federal SO2 limits. Unfortunately, the Kentucky Department of Environmental Protection (DEP) is way past the deadline for submitting a plan to the U.S. Environmental Protection Agency outlining steps to reduce SO2 in the area.
Putting waterways at risk
Smelter wastewater contains many pollutants that can harm aquatic life and drinking water supplies, such as mercury, lead, arsenic, and cadmium. Operators store the wastewater in onsite impoundments and discharge it into waterways.
Sebree discharges into three tributaries to the Green River and to Grane and Sputzman Creeks, all of which are designated as “high quality” water supplies and aquatic habitats. Given the environmental importance of such water bodies, it’s very concerning that Century has violated pollution limits for wastewater discharge over 20 times in the last few years, particularly for suspended solids that cloud water, block sunlight, deplete oxygen, and harm aquatic life.
The Hawesville smelter discharges wastewater directly into a segment of the Ohio River classified as “impaired,” which might be making matters worse for the River. Hawesville also discharged toxic pollution after DEP issued “one time” authorizations to do so numerous times over a few years. DEP is now looking into the issue and reconsidering its policy.
Better metal is possible
From Ford to Apple to Google, companies are pledging to purchase aluminum produced in lower-carbon, less-polluting ways. To help make those promises a reality, the U.S. aluminum industry will have to secure more of its energy from renewable sources and install better pollution control equipment. Both federal and state regulators need to update rules for the aluminum industry designed to protect air and water, some of which are decades out of date. And rules currently on the books and in operating permits must be enforced.
Today, over 70 percent of Kentucky’s electricity is generated using coal and another 20 percent with natural gas. “Greening the grid” may take time, but both state agencies and utilities—including Kenergy, which supplies the Hawesville and Sebree smelters—could move more quickly in this direction. Kentucky is the only one of five states with aluminum smelters that has yet to adopt a Renewable Portfolio Standard, a policy mechanism that helps increase the proportion of electricity from renewable sources.
In the era of climate change, the U.S. aluminum industry could have a bright future by contributing to energy and transportation transitions. To get there, companies need to first reduce their environmental and health footprint, for the sake of communities in Kentucky and beyond.