If you want to push a lot of people's fear buttons, tell them that a product will give them cancer. This is something that came up in a discussion about Philosophy's Purity cleanser (sparked by it being a sample product in the monthly Birchbox). Do I know if this cleanser's ingredients give you cancer or are dangerous? No, I don't. I'm not a chemist or a doctor, the only type of professionals really qualified to answer this.
However, a writer on another site took it upon herself to call the product harmful and say that its ingredients include carcinogens. Here are some things to keep in mind: Carcinogens exist everywhere in our environment. There is no way to completely shield yourself from them, and being exposed doesn't automatically put you in line for an early death. If that were the case, we'd all be gone. This writer didn't back her claims with a single medical journal finding, statistic, professional opinion, etc. But her article did so far to say that the product is deadly.
Here's another tricky thing: Cancer and its causes stump even the professionals. If it was a simple cause and effect, we would have created a cure for it by now and eradicated it. The causes are so varied and complex that to simplify it is irresponsible.
This is where blogging shouldn't go: No one who is not a medical professional should start trying to portray him- or herself as an authority in this area. Not only are you potentially putting yourself in line for a lawsuit, but you're also planting false fears in people and affecting companies' business, sometimes completely unjustifiably.
I was a journalist for 10 years, so I know both sides of it: The gnawing curiosity to learn more about the unknown and the danger of having a little information but not enough. If you're blogging, keep yourself in check about the potential harm you can cause. If you're reading a blog or watching Youtube, know that the free-for-all of information out there unleashes the potential for a lot of misinformation to be spread. Keep yourself informed, but watch out for being misinformed.
Disclaimer: I'm not angry. It's 97 degrees today; I'm hot, which I guess makes me feisty when I write.