tempered glass

hi! im doing a 300 gallon (68 by 30 by 30 inch) aquarium and i was wondering if i should use regular glass ( cost affective) or toughened/ tempered glass ( very expensive) my LFS told me that regular glass breaks easily and can actually kill people if broken! on the other hand i found no info...

I have drilled quite a few tanks so I got that part no problems there. I am thinking of putting together a fry rack with a central sump filter. I was going to use ten gallon tanks from Walmart, for me this is the cheapest option. Does anyone know if the tanks from walmart are tempered or not...