The U.S. Labor Department cited Ashley Furniture Industries for alleged safety violations for the third time this year on Monday and proposed an additional $431,000 in fines.

In a statement, the department's U.S. Occupational Safety and Health Administration (OSHA) said Ashley Furniture failed to protect workers from moving machine parts at its Whitehall, Wis., upholstery furniture plant that employs 475. The citation did not list worker injuries.

Ashley said in a statement that it will "vigorously challenge" the allegations.

OSHA said the proposed penalty "is in addition to the more than $1.8 million in fines issued earlier this year during inspections at other company facilities in Wisconsin."

A hearing before the Occupational Safety and Health Review Commission is being scheduled, OSHA officials said.

It is the latest hearing to be scheduled for Ashley, which in January received one of the largest fines in OSHA history. OSHA said in issuing the fine that Ashley's Arcadia, Wis., plant had more than 1,000 injuries, including several fingers being sliced off, because the company repeatedly failed to properly guard and power down machines.

Ashley officials have denied those allegations and are challenging the penalty. The company also is challenging an $83,200 fine levied in July by OSHA, which accused Ashley of not reporting another finger amputation in Arcadia.

The report on Monday cited similar failures to properly guard and power down machines at Ashley's Whitehall plant after an April inspection conducted as part of OSHA's Severe Violator Enforcement Program. The company received "one willful, five repeated and two serious citations," OSHA said.

"Ashley Furniture failed to implement required safety procedures to protect machine operators until after OSHA opened its inspection," said OSHA Eau Claire area director Mark Hysell. "The company must make immediate, enforceable safety improvements at its facilities nationwide."

The inspection revealed that managers failed to install locking devices or implement procedures that would prevent machines from unintentionally starting up or moving when operators changed blades, cleaned machines or cleared jams, OSHA said.

Ashley denied OSHA's allegations, and Paul Waters, the company's legal counsel, said OSHA inspectors" based their allegations on assumptions" and did not see many of the alleged violations.

"The claim that Ashley failed to protect its workers from moving machine parts is outrageous," Waters said. "At all times, Ashley has machine guards in place that are provided by the manufacturer and, in some cases, the company has gone beyond what manufacturers put in place by installing additional guards and implementing special procedures to protect workers."

Ashley's being classified a severe violator also resulted in inspections at its facilities in California, Mississippi, North Carolina and Pennsylvania, OSHA said.

Ashley, which is owned by the father and son team Ron and Todd Wanek, also produces furniture in China and Vietnam.

Forbes lists Ashley Furniture as the 117th-largest private company in America, with $3.85 billion in 2014 revenue. The company employs nearly 20,000 workers at 30 locations nationwide.