The accident occurred at the Continuous Cutting Machine Unit of RSRM Steel Mill in Bayezid Bostami of the port city on Sunday, Fire Service official Zahirul Islam said.
A part of the factory also caught fire when the liquid iron splashed. Fire fighters doused the fire, Zahirul said.
The four victims - Md Zafar, Md Zahir, Sanju Das and Abu Bakr - were admitted to Chittagong Medical College Hospital.
CMCH police camp's Nayek Abdul Hamid said 40 to 50 percent of the workers' bodies was burnt.
Iron is liquefied at 1200 degrees Celsius in the factory.
Source: Bangladesh's First Internet Newspaper