Someone I'm sure WILL correct me, but I believe the warnings are new, and inforced to get the items through customs. None of the products have been approved by the FDA, nor are they getting their cut from the profits, so they are trying to scare those of us still willing to use them. They also seem like fairly normal blanket drug warnings.
No, no one can reassure you of the safety, The FDA has not done testing to see if there are any real drug interactions. However, MY body is telling me that I'm healthier now than when I was smoking. I haven't droped dead or overdosed, I'm still taking my normal prescriptions with no abnorma effects or problems. I think you have to decide for yourself the level of risk your willing to take compared to smoking. For me its a NO brainer. 4000 chemicals or 4. I'm healthier, period.