there are many types of bamboo, but even walmart quit carrying a certain brand when they found out the chemical process used to make was actually leaving too many chemicals in the batting!
also there is this:
As far as it being "green". While bamboo grows quite quickly and is considered a sustainable source, it is my understanding that the process of turning it from plant to fiber (batting or cloth) involves a lot of nasty chemicals so the processing negates any "greeness" of sustainability and renewable source.