Re: Metal and Your Hookah.
This is by far the greatest invention besides beer, sliced bread, condoms, and skateboarding.
The exposure when using foil is there. There is transfer of chemical that burn off the foil and into the water. This is where most of them are caught and trapped into the water, but you will still pull some into your lungs. The burn off isn't in great amounts, cause the coals will essentially burn majority of chemicals of within a few minutes. The overall exposure is extremely slight and significant.
Keep enjoying that great invention.
I would think it would be the same for copper.... Copper needs a higher amount of heat for it to release gas that can be harmful. You also aren't sucking on the copper direct and there is no direct heat to copper when used. I would say any little harmful particles produced from the use of copper would get caught in the water and sink... no matter how small the particles..... Of course a little bit will get through.