WV Chemical Spill SHOULD WORRY YOU!! How many Chemicals HAVE NOT been tested for toxicity?

How dangerous is the chemical which was dumped into the water?  They have no idea.  Why was this chemical allowed to be tanked so close to a river which so many people get drinking water from?  Why was it so close to intake valves of municipal drinking water?

http://www.alternet.org/environment/5-reasons-west-virginia-chemical-spill-should-concern-you-regardless-where-you-live?page=0%2C1&akid=11411.294211.DwEjp_&rd=1&src=newsletter948243&t=17