American Chemical Society Prof. answers questions on Tianjin Blast fallout

May Nyman, a Professor of Chemistry at Oregon State University and active member in the American Chemical Society logged on to social media site Reddit to answer questions regarding the chemicals contained in the deadly warehouse blasts in China’s port city of Tianjin on Aug 12.

With a background researching new methods of storing and removing radioactive materials, as well ways to make water drinkable,  she is well poised to answer questions on what will become of the various chemicals – including 700 tons of cyanide –  exposed in the blasts.

Fallout of the chemicals has weighed heavy on rescuers, who donned bio-hazard gear as they tirelessly scrubbed the warehouse area, searching for survivors and desperately trying to contain the chemicals.

At one point, chickens and rabbits were brought to the warehouse site as a fail-safe warning against potentially toxic chemicals which could have avoided detection by digital equipment.

Two weeks on and the battle continues, with the death toll rising to 139 on Wednesday. with 34 still missing.  Residents of the port observed hundreds of dead fish washing ashore and storm puddles that contain a strange white foam, prompting fears of chemical waste.

For experts like Nyman, the aftermath reaches far beyond the shores of Tianjin,  tainting the world attitude toward chemicals.

“August 12, 2015 was a sad day for chemists when such a tragic accident happened that gives chemistry a bad name, and results in people fearing chemicals,” she said in her introduction to the AMA (Ask Me Anything).

In an attempt to clear the air, she took questions from users.  The full AMA session can be reached here.

Below are the highlights (some answers have been cut for length):

Q: JabawaJackson –   What is your hypothesis for an explanation of the explosion?

A: May Nyman (MN) Thank you for using the word hypothesis, because that is indeed all we can do here. My biggest suspicion is the calcium carbide as a starting point, because it is so reactive with water. Water is everywhere–its in the air (i.e. relative humidity is a measure of how much water there is in the air). If the calcium carbide is accidentally exposed to water through a hot humid day in an uncontrolled climate, a leak, a damaged container, it will start to react. acetylene is flammable and provides pressure, and could have been the source of the fuel for the fire.

That being said, it seems there should have been a spark that started the fire–human or instrument error: the same way forest fires start–a discarded cigarette or an electrical spark from a faulty wire or electrical cord.

 

Q:  Devidentarch321  – Did the firefighters spraying water on the factories have anything to do with the second explosion?

A: MN – thank you for this question. I will begin the answer with a note that, many thousands of miles away, we can only make educated guesses, based on the little information that we have onhand. Calcium carbide, is indeed a very suspicious player. It reacts quite violently with water to produce a flammable gas, acetylene, which is an ingredient in oxygen acetylene torches used in welding! So yes indeed, spraying water on calcium carbide is not a good idea.

 

Q: osheabutter – What, if any, long term effects do you anticipate for the area?

A: MN – The good news is, much of the chemicals present in the warehouse likely got destroyed in the two massive explosions. Anything organic converted to carbon dioxide, water and some form of nitrogen oxide. So large amounts of these gases, which are generally not harmful, could result in some changes in the local environment.

 

Q: hawkwings – Why would they have a large amount of cyanide there? Is cyanide or some version of it explosive?

A:  Cyanide is not really explosive by itself, and it can be neutralized (made harmless) with bleach. It is likely used in mining: it bonds to all sorts of metals.

It is also used to make other useful common chemicals such as polymers. I do not think it is stored for intentional use as a nerve gas.

 

Q: bongmastergeneral420 – Could you elaborate a little more on the fish dying and the soap sud rain?

A: MN –  These phenomenon are indeed curious. If we think about such a large explosion, what results is lots and lots of ash.  Ash is in fact the ingredient for making soap, the old-fashioned way. Ash is water makes lye (very alkaline water) which could react with road tar or oil, and you could get a very crude soapy material

Now about those fish. the pictures of many dead fish are pretty shocking. again, ash produces alkaline water, so perhaps it could be the alkalinity in the water went up (acidity went down), this is not the fish’s usual environment, which resulted in massive death.

 

Q: What goods will be affected by this break n the supply chain and when can non Chinese consumers expect to notice these effects?

A: MN – I suspect this will not be an issue. The chemical that we know of that were stored there are not specialty or rare. They are very common and there are many supplies and resources for these all over the world. 

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