A police officer tries to stop people, mostly relatives of missing firefighters, from unfurling a banner during a protest to demand information about those missing following Wednesday’s blasts, in front of the Binhai new district government building in Tianjin.

AFP/DPA/Tianjin

Hundreds of tonnes of highly poisonous cyanide were being stored at the warehouse devastated by two giant explosions in the Chinese port city of Tianjin which killed 112, a senior military officer said yesterday.
The comments by Shi Luze, chief of the general staff of the Beijing military region, were the first official confirmation of the presence of the chemical at the hazardous goods storage facility at the centre of the massive blasts.
The disaster has raised fears of toxic contamination.
Nearly 100 people remain missing, including 85 firefighters, though officials cautioned that some of them could be among the 88 corpses so far unidentified.
More than 700 people have been hospitalised as a result of Wednesday’s blasts – which triggered a huge fireball and a blaze that emergency workers have struggled to put out since then, with fresh explosions on Saturday.
State prosecutors said yesterday that they have started an investigation to see if dereliction of duty played a role in the disaster, the official Xinhua news agency reported.
Supreme People’s Procuratorate officials will work with authorities in the port city of Tianjin to gather evidence, Xinhua reported.
No employees from the warehouse’s owner, Ruihai International Logistics Company, or city officials have been held accountable for the explosions, Xinhua noted.
Four days after the blast, Chinese censors clamped down on rumours amid contradictory official announcements and state media reports.
The Cyberspace Administration of China suspended or closed more than 360 social media accounts and 50 websites after reports of looting and toxic gases blowing toward Beijing, about 120km from Tianjin, the official China Daily reported.
A fake US embassy warning notice to wash skin and rinse umbrellas was being widely forwarded across social media.
Preliminary testing showed ammonia levels slightly above safety standards within 2km of the blast, but the readings had since come down, the military’s Shi Luze said.
“We can say with responsibility the air quality meets standards,” he added,
But Tianjin’s environmental protection chief Wen Wurui told state broadcaster China Central Television that two of 17 air-monitoring stations near the site recorded amounts of highly poisonous hydrogen cyanide exceeding safety limits “for a short period”.
Hydrogen cyanide can be released by sodium cyanide, a highly toxic substance which although not explosive, can be deadly if inhaled when it burns or dissolves.
Authorities have yet to identify the cause of the explosion and have still not verified reports that 700 tonnes of sodium cyanide was stored at the blast site.
The chemical had been scattered by the blasts, but the quantity of the warehouse stockpile had not been confirmed by the government, the official Science and Technology Daily reported
In a sign of the potentially horrific nature of some of the injuries, the main state evening news bulletin showed yesterday a hospitalised patient whose head, face and neck were completely encased in thick white bandaging save for openings at the eyes nose and mouth.
Shi, who is a general, told a news conference that cyanide had been identified at two locations in the blast zone.
“The volume was about several hundreds of tonnes according to preliminary estimates,” he said.
Officials have called in experts from producers of the material – exposure to which can be “rapidly fatal”, according to the US Centres for Disease Control (CDC) – to help handle it, and the neutralising agent hydrogen peroxide has been used.
Authorities have repeatedly sought to reassure the public, insisting that despite the presence of some pollutants at levels above normal standards, the air in Tianjin remains safe to breathe.
Premier Li Keqiang arrived in the city yesterday afternoon to direct rescue efforts, a common move after major disasters in the country.
Pictures released showed the Communist Party number two within 1km of the blast site, dressed in an ordinary white shirt and not wearing a mask.
Xinhua reported late on Saturday that cyanide density in waste water had been 10.9 times standard on the day following the explosions.
It has since fallen but was still more than twice the normal limit.
Environmental campaign group Greenpeace said yesterday that it had tested surface water for cyanide at four locations in the city and had not detected high levels of the chemical.
“These results show that local water supplies are not currently severely contaminated with cyanide,” it said, but reiterated its call for comprehensive tests on the air and water and for publication of the results.
On Saturday a 3km radius from the site of the blasts was evacuated, state-run media reported.
Officials said later the reports were inaccurate but vehicles were turned back at barriers.
Yesterday AFP saw young men, carrying personal belongings, leave FAW Toyota apartments and board a bus waiting to take them to alternative accommodation.
Police in masks could be seen at one checkpoint.
Steve Ra, an American who was evacuated by his employer to another area of Tianjin, said he was worried about the potential health effects.
“The main concern is just the air,” Ra told AFP. “I’m waiting to go back to get my normal life back. But I don’t know what I’ll be breathing so that’s the biggest concern.”
Tianjin residents, relatives of the victims and online commentators have slammed local authorities for a lack of transparency, and tried to storm a news conference on Saturday.
Yesterday sobbing men confronted security at the hotel where officials have been briefing journalists, with one shouting “Police, I will kill someone!” in what appeared to be a desperate bid to attract attention before being comforted by a police officer.
Another lashed out at reporters attempting to photograph him, saying: “Don’t take my photo, it is useless. The news has no truth!”
Outside, residents of a building damaged by the blasts held a protest.
The government has moved to limit criticism of the handling of the aftermath, with a total of 50 websites shut down or suspended for “creating panic by publishing unverified information or letting users spread groundless rumours”, according to the Cyberspace Administration of China.
Critical posts on social media have also been blocked, and more than 360 social media accounts have been punished.
One poster on microblogging platform Sina Weibo wrote: “Why is it ‘rumours’ are flying everywhere every time there is a disaster? Are they really rumours?
“The government is lying ... You have lied to the people too much and made yourself untrustworthy.”