An early morning fire at a poultry processing plant in northeast China killed at least 112 people, state-run Xinhua news agency said. Another 54 workers were injured, reports CNN. Survivors told the news agency that about 100 workers escaped, only to find the gates to the plant locked.

State broadcaster CCTV quoted unidentified workers as saying the fire broke out during a change of shifts and may have originated in a locker room at a time when about 350 workers were at the plant, owned by Jilin Baoyuanfeng Poultry Co., reports Fox News.

A fire official told CNN that an explosion at the plant started fire, but added that the cause of the blast was not immediately known. Other reports noted the presence of ammonia inside the facility. The “complicated interior structure of the prefabricated house in which the fire broke out and the narrow exits” may have added difficulties to the rescue work, Xinhua reported.

Sources: CNN, Fox News