Mechanic Donald White, 63, was killed in June when he was hit by a counterweight at the bottom of one of the stadium's elevator shafts.
The state's Division of Occupational Safety and Health cited Schindler Elevator Corporation on Tuesday for three serious violations, including its alleged failure to enclose counterweights in freight elevators with required guards.
State officials also said Schindler Elevator failed to ensure that the elevator wouldn't activate while a worker was in the danger zone.
Each fine is worth a potential $18,000.
The company tells ABC7 News that it will vigorously contest the fines, given that investigators found no fault with the company in October.
White was the first of two workers to die while working on the new $1.2 billion stadium. The stadium is slated to open next year.
(The Associated Press contributed to this report)