Chittagong's chief doctor, Mohammed Elias Hossain, said some of the injured were in critical condition. Of the 200 or so injured, 50 were rescue officials, police said.
Troops were deployed to try to prevent the spread of chemicals into canals and along the nearby coast, officials said.
The last major fire in Bangladesh was in July last year when 54 people were killed at a food processing factory outside the capital, Dhaka.