Phthalate refers to any of a range of chemicals called phthalate esters, which are used in industrial contexts to increase the flexibility of plastics such as polyvinyl chloride (PVC). Phthalate is used in a variety of products other than plastics, such as personal care products, glues, paints, and pharmaceuticals. There are dozens of varieties of phthalate, which was first produced in the 1920s. They are made by reacting a chemical called phthalic anhydride with certain alcohols, which can be varied to give the end product specific characteristics.
Raw phthalate has the appearance and texture of clear vegetable oil, with little or no smell. It biodegrades readily, so it does not accumulate to toxic levels in the environment. Since their introduction, the phthalate group of chemicals has undergone extensive research and testing to find out what-if any- health risks they pose to humans. Some health concerns have been raised about the presence of phthalates in baby bottles and other items which would cause them to be ingested by people.
The concerns about negative health effects from phthalates have in some cases led to the phasing out of these chemicals in North America and Europe. Some jurisdictions have outlawed the use of phthalates in children's toys and similar products. These worries have arisen in the wake of effects observed in test animals in laboratory conditions. High levels of phthalates were observed to correlate with hormonal changes and birth defects, as well as other damage to the liver and reproductive system of rodents. Some studies have been done which also indicate harmful effects on humans from these substances.
Because of the ubiquitous nature of phthalates, the debate over their use has become somewhat politicized, as evidenced by the government regulations restricting their use in some places. Phthalates are used in some but not all types of PVC. PVC which is labeled as Type 3 for recycling purposes sometimes contains phthalates, although there is not usually a way to tell for sure, other than by chemical analysis. The presence or absence of phthalates is not required to be marked on PVC products. However, some manufacturers have done so anyway, in light of the concern many consumers have regarding these chemicals, especially in baby products.
While some studies indicate that phthalate poses dangers to humans and animals, others have found no such correlation. This fact means that the debate over their degree of safety is still unsettled. Many of the ill effects from these chemicals have only been observed in cases of unusually high exposure, and more testing and studies will need to be done to determine their safety.