I have worked for the company Durisol and I am very familiar with the product. I do know that it is very flame retardant you could put a torch to it and it will not catch fire. Also I was involved in the construction of their main production facility which is made out of the block and was very impressed. In the middle of an Ontario winter you could touch the inside walls and they were warm but if you touched the solid concrete column that was also inside it was cold as ice.

That may be, but I like the strength of a solid concrete wall and the increased R value of EPS.