blue rings are allowed to be imported because there are little to no federal regulation of aquatic species. you will notice many websites that are based out of Indonesia dont even warn that blue rings are in fact deadly. There is no antivenom anywhere however. Blue rings carry two toxins, the tetrodotoxin(found in a few other aquatics, including a puffer fish which is a delicacy served in japan as one wrong cut by a chef will kill you) is the main threat and is produced by bacteria in their saliva. The tetrodotoxin(a nuerotoxin) interferes with the nerves, basically rendering your vascular system paralyzed because the organs no longer get the commands to function[this is due to ion channels shutting down, your cells no longer can pump sodium and potassium into the cell which causes a failure of your nervous system to fire action potentials which are the source of signals in the nervous system]. the only treatment is artificial respiration that must be initiated within minutes of the bite, some bites if brief you might survive. most of the time toxin has gotten into you, there is simply no treatment and death is inevitable.
we actually just studied the effects of tetrodotoxin in my anatomy class this week
..this will probably get the thread moved..but it seems a necessary comment all the same.