I'm not an expert. The information contained herein is merely my opinion on information I have found during my own research.
This is an important issue that I believe does not get nearly enough attention in the vaping community and our society as a whole. Many have taken this issue up as a crusade to better educate people, since plastic is such a large part of our lives and is more than likely here to stay.
Certain plastics, and possibly plastic in general (studies are underway), is not suitable to be used in the construction of vaping components that come in contact, at any time, with eLiquid.
Many plastics contain either BPA ( Bisphenol A - Wikipedia, the free encyclopedia ), DEHP ( Bis(2-ethylhexyl) phthalate - Wikipedia, the free encyclopedia ), or both.
Both of these compounds are proven to be highly toxic in humans and animals with long-term or permanent side-effects. They also have a tendency to leech out of the plastic into materials they come into contact with.
While I do own a poly-carbonate tank, I will be replacing it with either a pyrex or steel tank very soon. I advise everyone else to do the same.
Manufacturers and vendors should be held accountable as to how safe their products are.
In addition, I've also concluded that acrylic is unsuitable as well, but for different reasons. Acrylic acid, used in the manufacture of acrylic products, is irritating and corrosive to certain organic tissues. http://en.wikipedia.org/wiki/Acrylic_acid