I did not know this. I had heard rumors, but I had never taken the time to do the research and sift the fact from the fiction. Bottom line is that PVC (polyvinyl chloride) is bad bad bad. Here are some reasons:
Thalates: Thalates are additives that are added to PVC to plasticize it, or to make it softer. PVC is often used to make children's toys, and it is suspected that thalates have leached out and been introduced to children. Studies have found a correlation in the amount of thalates in pregnant mother's urine, and shortness (or feminisation) of male babies genitals at birth. "According to some medical studies, the plasticizers added to PVC may cause chronic conditions such as scleroderma, cholangiocarcinoma, angiosarcoma, brain cancer, and acroosteolysis."--Wikipedia
Dioxins:dioxins are a common byproduct of the production of PVC. This is what it looks like:
According to my instrumental analysis teacher, dioxin is one of the most dangerous carcenogens. Also Wikipedia say: "At very low levels, near those to which the general population is exposed, dioxins have been linked to immune system suppression, reproductive disorders, a variety of cancers, and endometriosis."
PVC releases dioxins into the environment as it is incinerated in landfills, and as it is being produced. It can travel far distances, and thus is a global threat.
So why is it so widely used? Economics. It is used for almost any purpose under the sun. And it is cheap. Bottom line.
So, what can we do? Minimize vinyl usage. The recycle sign on the plastic bottle will have a 3 in the middle. Also, don't send your vinyl items to the landfill. Reuse it. The dioxins are released from being incinerated, and from sitting in the sun.