Blown or loose fill insulation
Loose fill insulation is made from shredded recycled paper or cardboard materials or pellets of vermiculite, slag or polystyrene beads, layered horizontally or poured into building cavities. Less energy use associated with production than for rigid products equates to lower environmental impact. High recycled content results in a lower impact.

Citations
Sustainable Design Resource Guide, AIA Colorado www.aiacolorado.org/SDRG