Tianjin warehouse explosion 2015

Fears of deadly cyanide gas reaction as rain forecast for Tianjin

City's vice-mayor admits the chemical has spread 1km from blast site, amid concerns it will react with rain to produce deadly compound

PUBLISHED : Monday, 17 August, 2015, 11:40pm
UPDATED : Wednesday, 20 June, 2018, 4:20pm

The explosions in Tianjin last week scattered sodium cyanide as far as 1km from the blast site, the city's vice-mayor admitted on Monday, as fears rose that rain forecast over the next few days could react with the chemical to release highly poisonous hydrogen cyanide gas.

Making his first public appearance since Wednesday's blasts, He Shushan, who is in charge of work safety in the city, explained his absence as due to a desperate attempt to search for and remove the chemical over the past few days.

He played down fears over its presence, saying that military specialists and government staff had twice scoured a 1km radius from the centre of the blast.

The death toll from the disaster rose to 114 on Monday, with 70 still missing, most of them "contract firefighters".

The relatives of some victims said they had been grounded in hotels, to prevent protests.

Authorities have been tight-lipped about the presence of sodium cyanide at the site. The first official confirmation of its existence there came from a Beijing military official on Sunday.

He's comments suggest city authorities knew of its presence at an earlier stage.

But the public received no official warnings about the chemical, and many residents and journalists have since accessed the 1km radius around the site.

Read more: What are the dangers of sodium cyanide?

Liu Hua, a Greenpeace campaigner, said: "It is really a pity the government did not inform or alert the public about the spill immediately. Sodium cyanide is a lethal chemical and could do huge damage to the health of those exposed to it."

The chemical can prove fatal if inhaled.

He said authorities had cleared a 2km radius from the blast centre, and as a precaution, a search of the 3km radius was to finish by last night.

Chemicals spilled at the blast zone's centre - about 10 hectares - would be the most difficult to decontaminate, said He, as some had entered the cracks of thousands of wrecked containers.

Several hundred tonnes of sodium cyanide were housed in the vicinity of the blast. But a military specialist said only a "relatively small amount" had been spilled. The rest had been located, but not yet retrieved.

Bao Jingling, a chief engineer at Tianjin's environmental protection bureau, said hydrogen cyanide in the atmosphere had been 8 per cent above safe levels at one point on Sunday at one of 17 monitoring stations, but no one was nearby to be harmed.

Read more: 'There’ll be no cover-up', Communist Party mouthpiece says 

Bao said there was a plan to contain the spread of hydrogen cyanide if rain were to fall.

A temporary enclosure has been built around the core blast zone to prevent leakage of polluted water.

But Liu had other fears.

"Sodium cyanide is not the only dangerous chemical at the blast site. It is almost impossible to predict what the rainwater will wash away as chemicals may react with each other. If there is any leakage outside the [temporary enclosure], chances are high the polluted water will end up in Bohai Bay," he said.

"As there is still no information on exactly what types and quantities of chemicals went up in the explosion, there is no way to gauge the scale of the environmental impact - how far it'll reach and how long it'll last."