LouiseLaws

All tampons are bad for health, because they are preventing your vagina from cleaning itself out naturally, also keeping a nutritious blood soaked wad of fibre, full of oxygen into your vagina further allowing bacteria to breed.
Commercial tampons are more harmful again because they contain unnecessary chemicals and bleach, which affect your natural PH, which can throw off the bacterial balance.
Also bare in mind the mucosa does not have the keratinized squamous epithelium that your skin does, so it has not got the same protection as your skin, skin itself is absorbent, mucosa however is far more absorbent and so more likely to absorb the potentially harmful synthetic chemicals in the commercial tampons.
Here in the UK we have the Notification scheme adopted for tampons (1984) was updated as a UK Code of Practice (COP) for tampons and ratified by the DTI/DoH in November 1997, this insures that tampons cannot be bleached with chlorine-bleaching and cannot use synthetic fibres other than Rayon. I would imagine the US has a similar thing, although I am fairly certain they do still allow chlorine-bleaching, which results in dioxin – which is the biggest risk that commercial tampon manufacturers have put our way. Other than that tampon manufacturers are self-regulated and self-tested, that’s not to say they are totally unsafe however, they do test for things like fibre loss in their tampons, any faults found in a batch then the whole batch is destroyed.
Tampax at large are more harmful because they are commercial tampons, they are also owned by Proctor & Gamble who are far from trustworthy. Tampax are made in way that they expand lengthways, which can often lead to increased period pain due to expansion into the cervix.
There was something about this make of tampon specifically, but by large it was an urban myth, I think Tampax did one of their ever so common cover-ups of the issue, whether true or not. So Tampax Pearl Tampons are about as safe as any other Tampax or commercial tampon, which isn’t very safe at all, but they are still used every day.
If you are concerned about your health when it comes to menstrual products then take a look at line, there is plenty of information on the risks associated with different menstrual products – although be sure not to trust everything you read, only go by reliable sources. If you are worried about what you use then why not try menstrual cups, they are the only menstrual product with no health risks associated with them at all, Keeper & Mooncup offer a three month money back guarantee and Divacup offers a years money back guarantee, they have a LOT of advantages over tampons, not just that they are safer but also greener, cheaper and convenient, with the money back guarantee they are at least worth a try.