Production was temporarily halted overnight at Ford Motor Co.'s Flat Rock Assembly Plant in Michigan after a female worker's leg got pinned in machinery.
The automaker said the accident occurred around 1 a.m. Friday and production was stopped for the night. It restarted later in the morning.
Ford did not provide further details about the worker or the extent of her injury.
"The safety and security of everyone in our plants is our highest priority," a Ford spokeswoman said in a statement. "We are launching a full investigation into this matter."
Ford employs about 3,500 workers at the nearly 3-million-square-foot plant, which builds the Ford Mustang and Lincoln Continental.