Green bricks?

Apparently someone has figured out how to take fly ash - which is produced as a pollutant byproduct by coal-fired power plants - and turn it into bricks.

This sounds great becuase normally fly ash has to be disposed of in special landfills. Not only that - but the technique uses a high-pressure system that doesn't cause the air pollutant emissions you typically get with "traditionl brick" - making techniques.

(Oooh, I can just see it: the brick-people-association, or whoever represents brick-makers, will be getting upset if this idea gains momentum)

My only question: fly ash contains mercury, lead and other toxic chemicals. I'd want to be pretty sure that my exposure was going to be verrry low if these bricks were going to be a part of any building where I spend a lot of time...