Several dozen people also were hurt in the blaze in Jilin province's Mishazi township, which appeared to have been sparked by three early morning explosions, the official Xinhua News Agency said. The provincial fire department, on its microblog, attributed the blasts to an ammonia leak. The chemical is kept pressurized as part of the cooling system in meat processing plants.
The fire was one of China's worst industrial disasters in recent years, with the death toll the highest since a September 2008 mining cave-in that claimed 281 lives.
State broadcaster CCTV quoted unidentified workers as saying the fire broke out during a change of shifts when about 350 workers were at the plant, owned by Jilin Baoyuanfeng Poultry Co.
It wasn't clear how many workers had been accounted for and a provincial government media official, who refused to give his name, said he expected the death toll to rise further as more bodies were recovered from the charred building.
It was difficult for workers to escape because only one door to the plant was open while other exits were locked and the fire spread quickly, state media quoted survivors as saying.
Some employees raised the alarm shortly after a shift began at 6 a.m., and then the lights went out, causing panic as workers rushed to find an exit, employee Wang Fengya told Xinhua.
"When I finally ran out and looked back at the plant, I saw high flames," Wang, 44, was quoted as saying. Xinhua said she and three other workers were sent to a hospital in the nearby provincial capital of Changchun.
Another worker quoted by Xinhua, 39-year-old Guo Yan, said the emergency exit at her workstation could not be opened and she was knocked to the ground in the crush of workers seeking to escape through a side door.
"I could only crawl desperately forward," Guo was quoted as saying. "I worked alongside an old lady and a young girl, but I don't know if they survived or not."
The newspaper Southern Metropolis Daily, known for its aggressive reporting, said the accident occurred in a factory building where chickens were being dismembered. The newspaper reported on its microblog that the fire spread rapidly, with industrial boilers exploding, and only a side door to the building was open with the rest of the exits locked.
It quoted an unidentified worker as saying the fire engulfed the building in three minutes, leaving too little time for many to flee.
The disaster killed 119 people, and 54 people were being treated in hospitals, the provincial government said on its microblog. Calls to fire and rescue services rang unanswered and hospital administrators said they had no information about the injured.
By about noon, the fire had been mostly extinguished by about 500 firefighters, and bodies were being recovered from the charred buildings. CCTV footage showed dark smoke billowing up from the prefabricated cement structures topped with corrugated iron roofs.
Chinese President Xi Jinping and other top leaders ordered that no effort be spared to rescue and treat survivors as well as to investigate the cause of the incident.
The fire highlighted the lax safety standards at many Chinese workplaces, despite efforts to compel improvements through regular inspections and fines.
It could also focus renewed scrutiny on China's biggest pork producer, Shuanghui International - unrelated to the poultry plant - as it aims to buy U.S. food giant Smithfield in what would be China's biggest takeover of an American company.
The poultry plant is one of several in the area where chickens are slaughtered and then quickly cut up into pieces and shipped to market. The entire process takes place in near-freezing conditions and such plants are usually built with large amounts of flammable foam insulation to maintain a constant temperature.
Jason Yan, technical director in Beijing of the U.S. Grains Council, said safety considerations usually take a backseat in China to features designed to maximize production and energy efficiency.
"I'm sure they consider some aspects of safety design. However, I think safety, to me, is not the first priority in their design plan," Yan said.
Jilin Baoyuanfeng produces 67,000 tons of processed chicken per year and employs about 1,200 people. The plant is located outside the city of Dehui, about 800 kilometers (500 miles) northeast of China's capital, Beijing.
Established in 2009, the company serves markets in 20 cities nationwide and has won numerous awards for its contribution to the local economy, according to introductions posted online.
The area where the fire occurred is an agribusiness center, especially for poultry. Nearby is one of the biggest producers of broiler chickens in China, Jilin Deda Co., which is partly owned by Thailand-based conglomerate Charoen Pokphand Group.
Monday's fire hit a company that is much smaller than Jilin Deda. Though it's unlikely to have an impact on China's chicken supply, the accident came as chicken producers were seeing sales recover after an outbreak of a deadly new strain of bird flu, H7N9, briefly scared the public in April and early May.
Associated Press writer Gillian Wong contributed to this report.