Ballots are being cast Wednesday over a pivotal decision at a Kentucky manufacturing complex that is producing batteries for electric vehicles. Workers will decide whether to join the United Auto Workers and extend a streak of union victories in the South, where organized labor struggled to find solid footing.

A two-day union vote closes Wednesday, about a week after production began at the BlueOval SK battery park, a nearly $6 billion joint venture between Ford Motor Co. and its South Korean partner, SK On.

Batteries from this plant will power the all-electric Ford F-150 Lightning pickup and its EV cargo van, the E-Transit.

Kentucky Gov. Andy Beshear says the complex that sprung up in tiny Glendale — a community of around 2,000 residents an hour south of Louisville — is the single largest economic investment in Bluegrass State history.

Pro-union employee Kumari Logan is looking for the security than she believes only a unionized workforce can deliver.

“My bills are guaranteed, so my pay and benefits should be guaranteed, too,” Logan said in comments emailed by the union. “Right now they can just change things whenever they feel like it, and that’s stressful. With a contract, you’ve got it in writing. You know where you stand.”

On-the-job-safety surfaced as another key issue for pro-union workers. The company says workplace safety is its top priority.

The company said it wants to maintain a “direct relationship” with its employees. When battery production started, BlueOval SK CEO Michael Adams said it is “creating good-paying, American jobs” while “strengthening the domestic supply chain and driving the transition to zero-emissions transportation.”

The battery complex includes two manufacturing plants but production has started at just one of them.

The fate of BlueOval is important to Gov. Beshear, a potential White House contender in 2028 who openly touts his pro-union credentials. He said the BlueOval SK project “sparked a surge of new investment and job announcements that placed Kentucky at the center of EV-related innovation.”

And organized labor has made inroads in the South in places that are not too different from BlueOval.

Workers at a General Motors joint venture electric vehicle battery plant in Spring Hill, Tennessee, joined the union. Workers at a Volkswagen assembly plant in Chattanooga, Tennessee, also voted to unionize. In Ohio, workers at another GM joint venture electric vehicle battery factory voted to join the UAW.

The union lost an organizing vote at two Mercedes factories in Alabama last year.

Domestic EV battery production is ramping up as the push toward electrification of the auto industry reaches a crossroads and as Chinese automakers expand across the globe, offering affordable electric vehicles and superfast charging stations.

Despite the unwinding by President Donald Trump of incentives meant to juice electric vehicles sales, the transition by Big Detroit automakers from internal combustion engines to electric is happening. Trump’s massive tax and spending law targets EV incentives, including the imminent removal of a credit that saves buyers up to $7,500 on a new electric car.

Ford recently said it will invest nearly $2 billion retooling a Louisville, Kentucky, plant to produce electric vehicles that it says will be more affordable, more profitable to build and will outcompete rival models.

The first EV to be produced by the revamped Louisville production process will be a midsize, four-door electric pickup truck in 2027 for domestic and international markets, the company said. The electric trucks will be powered by lower-cost batteries made at a factory in Michigan. Ford previously announced a $3 billion investment to build the battery factory.

The unionization vote in Kentucky may not be known until late Wednesday.