Not too much, but the fact that most are made using a tin foil bowl, when you light the tin foil and maby even the plastic around it the fumes of that can be harmful.
So having a 1$ pack of original zig zag's is always a better choice
"I hate to advocate drugs, alcohol, violence, or insanity to anyone, but they've always worked for me."
- Hunter S Thompson
All those numbers you see on bottles have to do with testing for heat resistance, strength etc. Some grade plastics have a lower heat threshold and can release a variety of nasty gasses which can cause you harm..
Joints are "healthier" for your lungs but i'm never giving up my bong
MPGH CA Section, Wow this little tiny box hold's alot of text.. HUH??? You think so.. Wow this isall
Actually guys.. U better go buy a pipe.. Ok 1. Foil is a no no.. ok im 22 and been smoking since been smokin.. If you smoke out of a pipe made of aluminum foil that causes lock jaw.. Seriously.. Brass also creates cancer.. Buy a glass piece