Quote Originally Posted by Gerald C Koch View Post
The naming of substances in chemistry is very important. The cyanATE ion is different from the cyanIDE ion. The LD50 for sodium cyanate is 1500 mg / kg which means you would have to ingest quite a bit of it before any toxic symptoms occured.
While that's true both Ferricyanide and Thiocyanate can liberate free Cyanide under extremes. That won't happen with home disposal by dilution but does raise issues where spent solutions are carried in a vehicle - the issue here is in an accident where battery acid could come into contact with the chemicals liberating Cyanide gas. I came up against this at work and the regulations are quite strict, you need to be a licensed carrier (which we were).

Ian