Tazreen Fashions Limited's certificate expired in June and was not renewed, Bangladesh Director of Fire Service and Civil Defense Abu Mohammad Shahidullah said Friday.
"We gave (the factory owner) a reminder he should contact us for renewal. It was not done. If they had come earlier the factory would have been checked by our inspectors," Shahidullah told the British Broadcasting Company.
Operating a factory without proper certification is an offense but the rules are often ignored, safety experts told the BBC.
Officials said more than 1,100 workers were in the nine-story factory on the outskirts of Dhaka when the fire broke out Nov. 24. Walmart subsequently said one of its suppliers had subcontracted work to the Tazreen factory without Walmart's consent.
Another official of the Fire Services Department, Abdus Salam, said fire extinguishers and other firefighting equipment at the factory were not used.
A government report on the incident is to be submitted in January, Salam said.