George Carlin had a great routine on this subject. He correctly surmised that we were all guinea pigs. His particular example was birth control pills but this could apply equally to any new chemical or product. We usually really don't know the full implications of something until it's been tested by the end user. There usually isn't sufficient "science" done beforehand to really trust a new drug or product. So we are ultimately all guinea pigs and we have to just see what happens.
Unfortunately by that point it's hard to isolate all the variables.
If cancers and allergies go up, who do you blame? There are so many possible culprits.
Also, science is much harder and much less certain than the talking heads will admit.