A unit of the Schwan Food Co. has been cited by federal regulators for seven significant safety violations stemming from three separate accidents in 2015 — all within three months of each other — at a Kansas frozen pizza plant.

Because of the accidents, one female Schwan’s worker lost a hand; another lost a finger; and a third suffered fractures and burns to one hand.

On Thursday, the federal Occupational Safety and Health Administration announced more than $172,000 in fines against Schwan’s Global Supply Chain, citing it for three repeated safety violations and four serious violations.

Marshall-based Schwan is a privately held frozen food manufacturer with over $3 billion in annual sales. The accidents occurred at the company’s plant in Salina, Kan., which makes pizzas under the Tony’s and Red Baron brands.

OSHA, after investigating accidents that occurred Aug. 11., Sept. 30 and Oct. 23, concluded Schwan’s had exposed its Salina workers to amputation and other serious hazards through unguarded equipment on the production line.

“Three women’s lives were dramatically altered because their employer failed to protect them from hazardous operating machinery parts,” Judy Freeman, OSHA area director in Wichita, Kan., said in a statement. “Schwan’s needs to protect their workers, and they need to do it now.”

In a statement, Schwan’s Global Supply Chain said it is “committed to ensuring the safety of the employees and contractors who work at our facilities. In that spirit, we appreciate OSHA’s findings. We are using the information gained from OSHA to improve our processes, and we are moving forward with their recommendations.”

In the August accident, a 55-year-old worker was picking up pizza crumbs when her work glove got caught in an unguarded conveyor chain and sprocket-drive assembly. After doctors amputated her right hand, she was unable to work for 55 days.

In September, a 39-year-old worker reached into a conveyor area to clear a pizza pan jam when her left hand was lacerated and fractured, and her palm burned. She lost 46 days of work. In October, a 55-year-old employee inadvertently put her hand into an unguarded chain and sprocket, losing the middle finger of her left hand.