Didn’t something similar happen in the Union Carbide spill in India back in ‘83?
The date of the Bhopal leak was Dec 3, 1984.
It was one of the worst industrial accidents known to have occurred, at that time.
It doesn’t appear to be similar, in that in Tianjin, there is seemingly no “chemical plant” leak involved, but there is a major port/storage area of huge quantities of a multitude of dangerous chemicals, awaiting shipment.
In Bhopal, it wasn’t cyanide.
I defer to other posters more familiar with dangerous industrial chemicals, to determine any similarities.
Bhopal, India was caused by 30 tons on methyl isocyanate. That is similar to what Tianjin is facing... But, probably not as bad.
I used to make NaCN. I dug out our handling brochure. Peroxide and Hypochlorite CAN be used as neutralizers... But, only in dilute forms. If contacted with concentrated NaCN, they’re both very bad news.
Basically... On a scale this size? I think the best they could do would be to evacuate, and spread some weak caustic soda ash over all the potentially contaminated areas. They must keep the water basic.... Even just a little.
God help them. If not handled properly, this has the potential to be catastrophic.