Recycling Plastic Bags into Childrens' Blocks

I learned about the method of "stewing" plastic bags from this instructable a while back, and decided to try it for myself.  In short, it's done by placing the bags in canola oil, in which they acquire a gummy consistency, suitable for molding into rigid pieces. I decided to make some childrens' blocks out of it. As far as I know the plastic is all #2 HDPE which I assume is safe for children. Can anyone shed some light on this? (don't worry I wouldn't give this to kids until I'm absolutely sure).

The swirly, marbled patterns have potential, although just mixing all the different colors together make it ugly as sin. Perhaps in the future I'll use various color schemes and they'll come out nicer.

On further thought, what basically gets created from this process is plastic lumber . Perhaps I can hang onto all my #2 plastic and slowly make enough plastic bricks to build a house. :) or even better, raid the bins on recycling day and live within other peoples' waste. Oh the possibilities....

Check out build pics at my flickr page.