The blaze, which swept through a poultry slaughterhouse, is one of China's worst industrial disasters in recent years.
A handful of men and women knelt in the middle of the road in Dehui in Jilin province to stop cars, while a crowd of more than 100 people gathered around them. Police dispersed the protesters after about an hour.
Zhao Zhenchun, who lost both his wife and his sister in the fire, said human error was to blame for the death toll. "I don't think safety was being managed properly. This should never happen again. They paid the price with their blood. So many of these big disasters in China are caused by lax supervision," he said.
The workplace safety record in the world's second-largest economy is poor. Fire exits in factories are often locked to prevent workers taking time off or stealing things, or blocked entirely, and regulations are easily skirted by bribing corrupt officials.
It is a record that will likely prompt concerns overseas as Chinese companies buy stakes in and take over foreign food producers, such as Shuanghui International Holdings's record $7.1-billion deal – including debt – to buy leading US pork producer Smithfield Foods.
State news agency Xinhua said those suspected of being responsible for the accident had been taken into police custody for further inquiries. It did not elaborate.
Local police said ammonia gas leaks could have caused the explosions in the plant, the Chinese News Service reported. The slaughterhouse is owned by Jilin Baoyuanfeng Poultry, a small local feed and poultry producer.
More than 300 workers were in the plant on Monday, with employees saying they heard a bang and then saw smoke, Xinhua reported. Around 100 workers managed to escape from the plant, whose gate was locked when the fire broke out, it added. Nearby houses were evacuated.
On Tuesday, Yang Xiuya sat cross-legged in front of a car and shouted angrily at police, insisting the doors of the slaughterhouse had been locked at the time of the fire.
"My daughter worked there. They haven't given us any explanation. It was time for my daughter to leave work but the door was locked, so they all burned to death," she shouted. "The government isn't giving us an explanation."
The death toll prompted President Xi Jinping – on a visit to Costa Rica before he heads to the United States for a meeting with US President Barack Obama on Friday – to instruct the authorities to care for the injured and find out what caused the disaster, Xinhua said.
Another relative screamed at a line of dozens of unarmed SWAT police officers and tried to attack them before women pulled him back. "We can't see our family members and there's no information. We can't see the survivors or the bodies of the dead. They need to let us see the bodies," he shouted, wiping away angry tears.
Many of China's deadly industrial accidents happen in the huge coal mining industry, in which more than 1 300 people died last year from explosions, mine collapses and floods.
Jilin is a largely agricultural province and an important producer of corn and soybeans. – Reuters