A release issued by the steel plant said that the incident occurred around 12.10 pm.
The three workers were rushed to a private hospital in the steel city, where their condition was stated to be critical, it said.
The incident is being investigated, the release said.
CITU leader Bansa Gopal Chowdhury, who visited the injured workers at the hospital, alleged that workers' safety was lax as the plant authority was keen only about production.