"This was a horrible accident," Lycoming County Coroner Charles E. Kiessling Jr. told the Williamsport Sun-Gazette.
The 35-year-old woman fell into the machinery around 11:30 a.m. at the Economy Locker Storage Company in Muncy Township, the coroner said.
It's not clear yet what may have caused the woman to fall, but Kiessling told the newspaper she was standing on a stair set with wheels and "was perhaps reaching for something in the grinder, which was about 6 feet off the ground."
Another employee at the plant reportedly found the victim. Her name was being withheld pending notification of her family.
The Occupational Safety and Health Association is investigating the woman's death.