My point was that clean coal can mean a lot of things and sometimes making one part of a product lifecycle "green" just passes the problem down the supply chain

My point was that clean coal can mean a lot of things and sometimes making one part of a product lifecycle "green" just passes the problem down the supply chain. In this case, scrubbing the flue gasses and recycling the coal ash resulted in toxic drywall. This isn't to say all drywall is toxic but it illustrates one illusion of something being clean or green.