A fire at a poultry plant in northeastern China early Monday trapped workers inside the building and killed at least 119 people, government officials and state media said.

The fire at the poultry rendering facility in Jinlin province apparently was caused by a buildup of ammonia gas, local officials said online.

 The blaze began shortly after 6 a.m. at a plant run by Baoyuanfeng Poultry in Mizisha, China’s state-run Xinhua News Agency said.

More than 300 workers were inside the plant when the fire began. A sudden bang was heard and dark smoke could be seen, according to Xinhua.

 Only one side door was left open, with all other exit doors locked, an employee in one of the factory’s workshops said in an interview with the Chinese newspaper Southern Metropolis Daily.

“The blaze ran through the whole workshop within three minutes, and fewer than 30 persons escaped,” the unidentified worker said.

Fifty-four people were injured, according to information posted by the provincial government on its microblog. Authorities sent 61 ambulances and more than 270 medical workers to help the injured, the government posting said.

According to emergency personnel interviewed by Xinhua, the plant’s “complicated” interior and narrow exits — in addition to the locked doors — made it difficult to rescue people.

“When I finally ran out and looked back at the plant, I saw high flames,” worker Wang Fengya, 44, told the news agency.

Another worker, 39-year-old Guo Yan, said that the emergency exit at her workstation was blocked, Xinhua reported. She said that she was knocked to the ground in the crush of workers trying to escape through a side door.

“I could only crawl desperately forward,” Guo said, according to the news service. “I worked alongside an old lady and a young girl, but I don’t know if they survived or not.”

 Hundreds of people protested outside the plant Monday afternoon, criticizing authorities’ reaction to the fire, according to the Southern Metropolis Daily, which had a reporter on the scene.

Some victims’ families said that police didn’t organize an effective rescue effort, and for several hours barred them from entering the plant to identify the bodies.

Police told local reporters that they kept people from entering the site for fear of disrupting the rescue and endangering additional people.

The Associated Press reported that President Xi Jinping and other leaders ordered an investigation into the fire’s cause.

 According to Xinhua, the poultry company has 1,200 employees and produces about 67,000 tons of chicken a year.

The plant is outside the city of Dehui, about 500 miles northeast of Beijing.

Established in 2009, the company serves markets in 20 cities nationwide and has won numerous awards for its contribution to the local economy, the news service reported.

Li Qi in Beijing contributed to this report.