As of Sunday morning, more than 50 people have been rescued in Tianjin, city government spokesman Gong Jiansheng said. They include a 19-year-old firefighter who lay on the ground for hours with burns and a cracked skull until he was found, officials said.
On Saturday, fires sent plumes of black smoke skyward near where explosions devastated a chemical warehouse in Tianjin on Wednesday.
But officials denied news reports that an evacuation order had been immediately issued for everyone within 1.8 miles (3 kilometers), with Gong calling the reports "false information."
The Beijing News, citing the People's Armed Police Force, had reported the evacuation order. CNN has reported that at least one disaster recovery shelter is located within the reported evacuation zone.
However, photographs made it appear that vehicles in a parking lot had caught fire rather than new explosions having taken place at the warehouse, as the Xinhua news agency had reported.
'Lessons paid for with blood'
Chinese President Xi Jinping said Saturday that the Tianjin blasts and other recent accidents exposed severe problems in workplace safety and urged authorities to heed "safe growth" and "people's interest first" in efforts to avoid such accidents, Xinhua reported.
The president also "urged authorities to learn from the 'extremely profound' lessons paid for with blood" in the Tianjin explosions, Xinhua reported.
Xi is demanding improvements to workplace safety, the agency added.
The first blasts on Wednesday, one of which carried the equivalent of more than 20 tons of TNT, left more than 700 people injured and thousands homeless, officials said. A man around 40 years old was reported to have been rescued from the site on Saturday.
Flames at the warehouse appeared Friday to be largely extinguished but residents worried about lingering contamination.
"I asked my in-laws to take my daughter home. I don't want them to stay here," Tian Binyan, a migrant worker, said. "I'm worried. I heard it's going to rain later and that would make the air toxic."
She was among the 6,000 people displaced by the fire and explosions that rocked the port Wednesday night, sending fireballs many stories high.
What chemicals did the warehouse store?
Tianjin officials said they were unable to give a detailed list of the chemicals stored at the warehouse.
Gao Huaiyou, the deputy director of the city's Work Safety Administration, said Friday the warehouse was a temporary storage facility. Materials were kept there briefly after they arrived at the port and before they were transported elsewhere.
The warehouse was destroyed by the explosions, he told reporters at a news conference, and managers of the facility have provided "insufficient information" about what was stored there.
But sodium cyanide, a highly toxic chemical that can kill humans rapidly, was one of them, Gao said.
The environmental group Greenpeace, citing a local monitoring station, said it believed other dangerous chemicals stored at the site included toluene diisocyanate and calcium carbide.
Gao said further investigation, including checks of customs records, would be needed to establish the types and amounts of the chemicals at the warehouse.
What is the environmental toll?
Chinese officials sent chemical and biological experts to the scene, and 1,000 firefighters were still there on Friday, pouring foam and sand on lingering hotspots, according to authorities.
Wen Wurui, Tianjin's environment protection chief, said Thursday that some chemical levels in the area were higher than normal but they would not be dangerous to humans unless someone were exposed to them for long periods.
And environmental officials said they had found nothing unusual in the waters off Tianjin, state media reported.
But Greenpeace warned that rain could pose more challenges by setting off reactions and washing chemicals into the ground.
Liu Yue, a 25-year-old who lives about 2.5 miles (4 kilometers) from the site said she and others were taking precautions against possible contamination.
"I've told my parents not to drink tap water," she said.
What caused the blasts?
Fire officials said hazardous chemicals stored at the warehouse were ignited by fire. The cause of the fire has yet to be determined.
Executives from Rui Hai International Logistics Co., the company that owned the warehouse, have been taken into custody, state media reported Thursday.
Lei Jinde, an official from the Chinese Public Security Ministry's firefighting bureau, told thepaper.cn, a Shanghai-based newspaper, in a telephone interview that the first team of firefighters used water in an attempt to contain the fire. It was necessary to cool the blaze, he said, according to a CNN translation.
But water isn't the best fire suppressant for some chemicals.
Calcium carbide reacts with water to form acetylene, which can catch fire.
"We knew there was calcium carbide inside, but no one had knowledge if it was exploding or on fire," Lei said. "It's not that the firefighters were stupid that they would still use water after knowing there was calcium carbide. I didn't mean that. We absolutely can't say it was wrong to use water."
Authorities in Tianjin appeared to have been concerned recently about the handling of hazardous materials at the port.
A notice posted by the Tianjin Administration of Work Safety on its website last week said city officials held a meeting with executives of more than 20 companies that handle dangerous chemicals at the port.
How many lives did the explosions claim?
Of those confirmed dead, 21 were firefighters. Many people are still missing, including dozens of employees of the company that owned the warehouse, according to the Xinhua news agency.
One firefighter was rescued from the rubble Friday, Xinhua reported.
One of killed firefighters was recovered at the rescue scene, and about a dozen other firefighters flanked and stood over the covered body in a solemn ceremony, according to CCTV.
The comrades took off their helmets and bowed four times in a moment of reverence at the rubble-strewn site, according to footage by China Central Television, the nation's largest national broadcasting network.
Some of the firefighters carried the body away on a stretcher, and the remainder saluted as the body passed by, the network footage showed.
The death toll could have been higher had the explosions occurred during the day, when more people would have been working in the area.
The district in which the warehouse was located is thinly populated. It is roughly 25 miles (40 kilometers) from the center of the city, a sprawling metropolis of more than 13 million people. About 90,000 people live within a 5-kilometer radius of the blast site, the China Earthquake Networks Center said.