EV Batteries’ Chemical Risks to US Workers Rising as Plants Grow

The calls to the Lordstown, Ohio, fire department began trickling in shortly after a new electric vehicle battery plant—a joint venture between LG Energy Solution and General Motors Co.—opened in August 2022 in nearby Warren.

Fires from overheated cells. Inhalation of chemical fumes. Acid spills potent enough to eat through flesh and bone.

When the company, Ultium Cells LLC, invited firefighters for a meeting at the plant, chief Travis Eastham thought they would be getting information on how to handle chemical injuries.

Instead, “we sat through an infomercial on why you should go electric,” Eastham said. “It was kind of a waste, honestly.”

The plant was the site of an explosion in March 2023, and Ultium faced fines of $270,000 after the US Occupational Safety and Health Administration found 19 violations. “OSHA inspectors found the company exposed workers to machine and chemical hazards by failing to use and train workers on safety and emergency response procedures,” the US Department of Labor said in a statement. Ultium is contesting the fines in administrative court, according to OSHA enforcement data.

While the fire risks of lithium-ion batteries that power electric vehicles have made headlines around the world, the dangers from the batteries’ chemical powders, liquids, and fumes are not as well known—and the risks to American workers are increasing as more EV batteries are made in the United States.

So far in 2024, OSHA and its state partners have issued citations for 47 violations. That’s already more than the 44 violations alleged in 2023 and a 147% boost over the 19 violations found in 2022.

Among the companies cited were Ultium Cells, which provides batteries for GM vehicles; SK Battery America in Georgia, a subsidiary of the Korean-based SK that supplies batteries for Ford Motor Co. and Hyundai Motor Co.; and LG Energy Solution Michigan Inc., which supplies Ford, Stellantis, Volvo, and GM, and is part of LG Energy Solution.

LG Energy and SK Battery declined multiple requests to discuss their production process and OSHA cases. Ultium Communications Manager Katie Burdette said that since November 2023, when OSHA began an inspection that found 17 alleged violations, the company has worked closely with OSHA and the United Auto Workers “to have a constructive and collaborative dialogue on how we can build upon our existing safety program and deploy best practices as a model for others in an emerging.”

Ultium didn’t respond to subsequent questions about Eastham’s criticism of first responder training. The fire chief said he felt the company’s practices had improved in the two years since it opened.

The rise in safety and health cases is predictable for a US industry in its infancy—the oldest active EV battery plant dates back to 2010—and without an experienced workforce, said Robert Galyen, the retired chief technical officer of Contemporary Amperex Technology Company Limited, the world’s largest lithium-ion battery manufacturer and now a consultant on lithium-ion battery production.

“Battery manufacturing is difficult. It’s a bunch of noxious chemicals you throw into a box and you make it perfectly safe to put into a car,” said Galyen.

For many chemicals and metals, there is a lack of scientific study on long-term exposure effects. While the Centers for Disease Control and Prevention have issued exposure guidelines, most aren’t covered by specific OSHA exposure limits. For chemicals without an OSHA-set exposure limit, the agency doesn’t have specific rules for employers.

Metals used in lithium-ion EV batteries such as nickel, lithium, and cobalt are known to cause a variety of ailments, from cancer to nerve damage. And yet the extent of the risks posed by handling these materials is just beginning to come into focus.

“Some of the materials have been out for so long—some of them are elements—and you don’t have a lot of scientific study or limits. It’s almost unbelievable to some people,” said Robert McCafferty, who worked at Tesla Inc. for five years as senior director for environment, health, and safety, and now holds a similar job in the medical product industry.

OSHA’s time-consuming rulemaking process—a regulation to protect health-care workers from airborne diseases has been in development for 15 years—makes it unlikely the agency will directly address lithium-ion battery manufacturing hazards in the near future.

Andrew Wallender/Bloomberg Law

What’s in the Box

Workers can be exposed to potentially hundreds of chemicals in building a lithium-ion battery.

The first stage is creating the electrodes, which often begin as a roll of thin metal such as copper or aluminum. The rolled metal is unspooled into a machine where a wet slurry is applied to the thin metal. The slurry can include powdered metals such as nickel, cobalt, manganese, and other ingredients mixed with a liquid solvent, often the hazardous liquid chemical N-Methylpyrrolidone. Workers need to be protected from coming in contact with the slurry by the use of respirators, protective clothing, and gloves, Galyen said.

Companies could also protect workers by enclosing the mixing process so that workers don’t come in contact with hazardous substances, said Darius Sivin, an occupational health specialist and investigator with the United Auto Workers. For example, bags of powdered metals could be placed inside a sealed container so that workers outside the container would remotely open the bag and dump the bag’s contents into a mixer.

The coated metal is then dried in an oven. During drying, the chemical solvent’s vapors are vented away for liquefaction and reuse.

The slurry application and drying are largely automated, but workers would sometimes need to enter the machines to undo jams or perform regular maintenance on the rollers. Companies are required to ensure machinery can’t injure workers, but shutdown procedures may be rushed and workers could lack training.

“These things are merciless,” Galyen said. “They’ll either rip your clothes off or drag your flesh into these rollers.”

Once the coated metal is dried, it’s cut into pieces that fit inside battery casings. Then, a toxic liquid lithium-ion electrolyte is pumped into the casing to create the basic component of an automotive lithium-ion battery—the cell.

The cells are sealed and placed on storage racks where they get an initial electric charge. Once a cell is minimally charged, gases inside the cell may need to be vented out, a process called “degassing,” with the gas being mostly carbon dioxide and some carbon monoxide, said Donal Finegan, a senior scientist at the US National Renewable Energy Laboratory in Golden, Colorado.

After degassing is complete, the cells are sealed shut and grouped together to create battery modules that can then be encased in modules ready for delivery to car plants. Workers handling the cells need to wear gloves, respirators, and protective clothing to keep them from contacting the electrolyte or fumes, Galyen said.

A health concern for the UAW’s Sivin is that workers often don’t know what chemicals are used because companies treat the recipes as trade secrets. While a manufacturer may have to share the ingredients with government regulators, the disclosure doesn’t extend to workers or the public, he said. The mixtures often change as companies try to improve battery efficiency.

“The electrolyte is often the most protected secret sauce of every company,” Finegan said.

Photos of battery manufacturing often show workers wearing spotless white overalls and hairnets on factory floors that are brightly lit and equally spotless.

That clothing doesn’t significantly protect workers from chemicals, Sivin said. Instead, the coverings are intended to prevent workers’ hair, sweat, and skin from contaminating unfinished batteries.

“The purpose of a clean room is to protect the product from the worker, and not the other way around,” he added.

Beyond the obvious dangers of lithium-ion batteries that catch fire, the smoke is a mix of toxic chemicals and metals that can include hydrogen fluoride, carbon monoxide and dioxide, hydrogen, methane, and manganese, said Justin Milne, a senior engineer with the fire safety firm Jensen Hughes.

For example, OSHA cited SK Battery’s plant near Commerce, Ga., for an Oct. 3 fire that the agency concluded SK Battery’s in-house fire department wasn’t prepared for. The agency said that at least 18 workers had been at risk for exposure to hydrofluoric acid vapors released during the fire and that first responders lacked training or experience to fight a battery fire or treat workers for inhalation hazards.

In addition to the hazards to workers posed by the smoke, a plant after a fire could face a costly shutdown as the chemicals and metals left on surfaces by the smoke are cleaned up to ensure there is no contamination once production resumes, Galyen said.

OSHA’s Standards

OSHA doesn’t have regulations specifically aimed at lithium-ion battery manufacturing. That may lull some battery manufacturers into thinking OSHA doesn’t regulate them.

“If you’re a small company, and don’t have someone who knows what they are doing with these materials you think, ‘Oh, everything is OK because OSHA said it’s OK,’” said McCafferty.

Companies need to exceed OSHA’s requirements in order to protect their workers, said Dr. James Craner, who served five years as a full-time and consulting occupational health physician with Tesla and is a consultant for battery manufacturers and mining operations.

“OSHA simply provides the ground rules for the minimum standard of care,” Craner said. “It doesn’t provide the methods, it doesn’t provide the tools, and it’s certainly a far cry from best practice.”

The closest OSHA has come to issuing specific requirements for lithium-ion battery makers is a 2021 interpretation letter that said employers are required to follow the agency’s hazard communication rule, which requires workers to be educated about the dangers of the chemicals they could be exposed to, and how to prevent and handle exposures.

OSHA declined interview requests to discuss the violations, which are being contested in court; how it is preparing inspectors for battery plant inspections; or if the agency will issue more guidance directed at battery plants.

“The industry needs to take hold of these health and safety issues as an essential business process and then show OSHA how it is done rather than the other way around,” Craner said. “Instead of 28 different companies each doing its own thing, do one thing and share the information.”

The UAW’s Sivin said workers at unionized battery plants can have greater leverage on health issues than non-union workers. For example, the UAW’s master contract with GM requires the company to follow chemical exposure limits set by the American Conference of Governmental Industrial Hygienists, whose limits are often stricter than OSHA requirements and cover chemicals OSHA hasn’t set limits for.

A common thread among the OSHA citations is that employees, including temporary workers, weren’t aware of the hazards or actions they could take to protect themselves. Educating workers about lithium-ion battery production is a challenge the Department of Energy and Department of Labor hope to resolve by developing training curricula with the industry via the Battery Workforce Initiative, said Betony Jones, director of the Energy Department’s Office of Energy Jobs. The initiative, which is still in its early stage, is largely focused on training machine operators and machine repair technicians.

The Ultium plant in Warren may be a harbinger of the nascent industry’s trajectory in dealing with chemical hazards. When the plant first opened two years ago, officials witnessed injuries rarely seen at the old GM assembly plant that used to run nearby, said Eastham, the Lordstown fire chief. Many of them had to do with exposure to hydrofluoric acid—a corrosive agent that can eat clear through flesh and bone—created with damage to a battery cell.

The machine technology was new to the US, and unfamiliar to employees who had never worked in an EV plant, Eastham said.

“They didn’t understand the machinery until they got in and started running it,” he said.

Calls have slowed as officials at Ultium have learned how to prevent and treat wounds, he said. Lately, it has been treating injuries with its in-house medical department.

“It’s a work in progress on where they’re going from where they started,” Eastham said. “They’re getting there. It’s just a lot of unknowns that they’re learning from.”