At least 119 people were killed when a massive fire broke out in poultry processing plant in Jilin province. More than 50 people were injured.
The Jilin Baoyuanfeng Poultry Plant employs about 1,200 people. An estimated 350 workers were on site when the fire began.
The plant's narrow hallways, a locked front gate and what survivors explained as "complicated interior" made escape difficult, according to local media reports.
"I could only crawl desperately going forward," 39-year-old Gao Yan told the state-run news agency Xinhua. She said the emergency exit near her station was blocked and she was nearly caught in a stampede to escape.
Xinhua reported the fire was sparked by three early morning explosions. It was reportedly linked to blasts from an ammonia leak, according to the provincial fire department.
CCTV quoted unidentified workers who said the fire may have started in a locker room.
The incident spotlights lax safety standards in Chinese factories and highlights concerns over the impending takeover of US food giant Smithfield by Shuanghui International, though Shuanghui is not related to the poultry plant.
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, The Associated Press reported.
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.
Some employees raised the alarm shortly after a shift began at 6 a.m., and then the lights went out, boosting the level of 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.
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, on its microblog, reported 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.
Calls to fire and rescue services by the AP 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.
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.
The Associated Press contributed to this report.