Answer:
staw or straw? But, never the less, normal insulation hurts the environment. while being manufactured, the factory's blow smoke. while straw/staw do not have to be built, so there for wont hurt the environment.
Explanation:
I know this isn't answering your question but i think you will find it useful to visit the link pasted below. i just visited it and it explains pretty much everything about this.
