Sodium cyanide threat in Tianjin

More than 110 people have died and close to another 100 people are still missing after massive explosions destroyed a chemical warehouse in Tianjin, China.

In addition to immediate concerns of finding missing colleagues and loved ones, residents of the port city may now also have to worry about environmental consequences: toxins could have been spilled into the water surrounding the plant, and fumes could pollute the air.

Information about what exactly was stored at the warehouse, and how much of it, is only slowly trickling down. What is known: There were hundreds of tons of sodium cyanide there - even though the warehouse was only allowed to store 24 tons, according to reports from the "Beijing News" paper.

David Santillo, a senior scientist at the Greenpeace Research Laboratories in Exeter, the United Kingdom, told DW that until there are harder facts on which chemicals exactly were stored at the warehouse, it will be difficult to predict exactly how the explosions and the aftermath could affect the environment.

But the release of sodium cyanide alone, Santillo told DW, could have devastating environmental consequences.

Danger in the water

"Sodium cyanide is extremely toxic," Santillo said. "It acts very quickly by poisoning the respiration system. It will affect every animal, and of course humans."

Sodium cyanide is a salt that is used for various purposes, for example to create anti-rust coatings for metals, or in the fertilizer industry. One thing that makes it even more dangerous is the fact that contact with water creates a poisonous acid.

"We don't know yet whether there are links between the nearby river and obstruction points for drinking water," Santillo said. But if there were, it could spell disaster.

Cyanide can persist in groundwater for a long time. Fish that live in the river, as well as animals living on contaminated soil, would suffocate as the chemical enters their respiratory systems. The same goes for humans, should the cyanide enter the drinking water.

"You only need micrograms of sodium cyanide for it to be toxic," said Santillo. "That's a millionth of a gram in one liter of water."

Danger in the air

But the cyanide doesn't have to get into the water to cause trouble. The newspaper "Beijing Times" has reported that authorities wanted to evacuate the area in a 3-kilometer radius out of fear of toxic gases.

"The other problem with cyanide is that in the fire itself, sodium cyanide would have in part converted into hydrogen cyanide gas," Santillo said. This gas could make for toxic fumes, the researcher added: "It inhibits respiration very quickly."

Because the exact composition and amount of chemicals that were stored in the destroyed warehouse is still unknown, it's not clear whether rain would actually improve the situation after the fire - or make it worse.

"Rain could help to reduce the amount of contamination in the air so that people are breathing in less," Santillo explained. "But obviously, it could also increase the amount of contamination in the soil and in the groundwater."

Other chemicals reportedly stored at the warehouse include ammonium nitrate, potassium nitrate and calcium carbide.

Chinese authorities have yet to release official reports on the topic.