There's a lot of greenwashing in the insulation business. Rockwool uses coal to melt stone, binds the fibers with formaldehyde, and puts the coal ash waste in

There's a lot of greenwashing in the insulation business. Rockwool uses coal to melt stone, binds the fibers with formaldehyde, and puts the coal ash waste in the final product. That's not something I want deteriorating in my walls.