Polyvinyl chloride (PVC) is a hard, brittle plastic. It is only when softeners are added that it becomes softer and pliable and can be made into floors and other products. In the past, manufacturers used phthalates for this purpose. In soft PVC floorings these are not securely bound, but can evaporate or wash off from the products or escape into the room as a result of wear. Humans can absorb phthalates from the air, via food or through the skin. Low molecular weight phthalate compounds are hazardous to health, as they are thought to imitate hormones and cause conditions such as sterility, overweight and diabetes in men.

Furthermore, phthalate softeners are also present in many baby items and toys.