Humans and the environment are constantly being exposed to many different chemicals. We know that chemical substances can interact in such a way as to greatly increase risk.
The hazards contained in chemical substances are generally assessed on a substance by substance basis. Some substances when combined can pose a greater risk than they do when assessed separately. Another name for this is the cocktail effect.
We currently know too little about which aggregated effects might arise. In order to manage this situation, we need to improve both our knowledge about the hazardous properties of a single chemical substance and our understanding of the potential effects this substance can have when combined with other substances.
One difficulty is that the legislation does not allow for the imposing of severe restrictions where risks are suspected to exist. This is because the regulations are primarily targeted at a single chemical product or substance.
Moreover, there are still no effective methods for estimating whether any combination effects might occur or how great the risk of damage might be.