Chinese authorities have evacuated thousands of people from three kilometres around the site of deadly explosions in Tianjin after discovering sodium cyanide among other toxic chemicals.
The exclusion zone was brought in on Saturday, three days after the blasts that killed at least 105 people.
At least seven smaller blasts were recorded yesterday, including in a car park next to the explosion site, as firefighters continued to tackle blazes across the port area.
Warning: Footage contains strong language
Zhou Tian, the head of Tianjin Fire Department, said: “Many types of different materials with different characteristics are mixed together and could at any time result in a chemical reaction or explosion.”
Government officials initially refused to comment on residents’ fears that the volatile cocktail of industrial chemicals that caused the disaster had spread into the air and water.
But this morning, the official Xinhua news agency confirmed that the exclusion zone had been introduced “for fear of chemical contamination”.
Photographs showed government chemical warfare specialists at the still smouldering site wearing protective clothes and gas masks.
The state-backed People’s Daily newspaper tweeted that they had sent to handle “toxic sodium cyanide” discovered in the devastated port area.
The compound is among the most rapidly acting poisons known when ingested or inhaled, and an oral dosage as small as 200mg can be fatal.
At a news conference on Thursday, Wen Wurui, a senior environmental official, had played down the threat of contaminated air and claimed emission readings had dropped to safe levels.
Meanwhile, the Tianjin Internet Police issued a warning that anyone spreading “rumours” about the disaster and its effects would be “severely dealt with according to the law”.
Comments criticising the emergency response on social media were deleted by authorities and blogs sharing news were shut down.
Tianjin Explosion - In Pictures
Tianjin Explosion - In Pictures
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A man wearing a mask walks past overturned shipping containers after explosions hit the Binhai new district in Tianjin. Two massive explosions caused by flammable goods ripped through an industrial area in the northeast Chinese port city of Tianjin late on Wednesday, killing 17 people and injuring around 400, official Chinese media reported.
A screen grab from taken from state broadcaster China Central Television (CCTV) footage on August 12, 2015 shows a huge explosion in the northern Chinese port city of Tianjin.
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Excavators work near the site of the explosions at the Binhai new district, Tianji
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A man who was injured following the massive explosions at the Binhai new district in Tianjin receives medical treatment at a hospital.
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View of the destruction after explosions in the port area of Tianjin, northern China,
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A emergency worker is lifted by a crane as smokes plumes from the explosion site in Binhai new district in Tianjin
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A damaged truck is seen on a highway near the site of the explosions at the Binhai new district in Tianjin
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Flames rise as a banner in the background reads "no illegal operations" at the site of a series of explosions in Tianjin, witnesses described a fireball from the blasts ripping through the night sky.
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Smoke rises from shipping containers after explosions at Binhai new district in Tianjin, China.
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Firefighters take a break after trying to put fire down at the explosion site in Binhai new district in Tianjin,
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A survivor talk on his mobile phone at the site of the explosions at the Binhai new district in Tianjin
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Firefighter's truck and other rescue vehicles are pictured as smoke rises among shipping containers after explosions at Binhai new district in Tianjin
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Damaged cars are seen near the site of explosions at the Binhai new district in Tianjin
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A paramilitary policeman wears a mask as he blocks the road leading to evacuated residential area and the explosion site in Binhai new district in Tianjin
Today’s exclusion zone was brought in as angry relatives of around 25 missing firefighters stormed a government news conference, demanding information on their loved ones.
“We have gone to each and every hospital by ourselves and not found them,” said Wang Baoxia, whose elder brother has not been seen since he left to fight Wednesday’s fire.
“There is no government official willing to meet us. Not even one.”
State media reported the rescue of a survivor this morning but hopes are fading for dozens of people who are still unaccounted for.
Firefighters had been called to a warehouse storing toxic chemicals 40 minutes before the explosions started at around 11.30pm local time on Wednesday.
Two huge blasts, including one with the force of 21 tons of TNT, came just 30 seconds apart. They were so large they could be seen from space and were registered by earthquake sensors.
Ruihai International Logistics had reportedly been storing chemicals including sodium cyanide, toluene diisocyanate, ammonium nitrate, potassium nitrate and calcium carbide.
"I do feel a bit afraid," said construction worker Li Shulan, when asked about the air quality. "It definitely doesn't feel good. As you can see our boss is making us wear masks."
About 6,300 people have been displaced by the blasts and around 720 people were injured, including 33 who are in a serious condition.
Additional reporting by Reuters and PAReuse content