There is growing concern that combined exposure to chemicals from different sources used for example in agriculture and industry may have adverse effects on human health, even if each individual substance is below its own risk limit. The Environment Council has adopted conclusions on these combination effects.

Experts regard the predominant chemical-by-chemical approach in risk assessment as insufficient to protect against the risks of combination effects. The conclusions therefore call for more research in the area. Furthermore, the Commission is invited to assess how and whether existing legislation addresses this problem and to suggest appropriate modifications and guidelines, paying attention to the precautionary principle in future legislation.

The focus is particularly on endocrine disrupters. These are substances that act like hormones and disturb the normal functioning of the endocrine system. The endocrine system is a network of glands and hormones that regulate many of the body's functions, including growth, development and maturation. Endocrine disrupters are suspected of interfering with the production and performance of hormones. Such effects have already been seen in animals, impairing reproduction, development or immunity.

A number of studies show that multiple endocrine disrupters can be linked to harmful effects on human health. Exposure may be through food, plastics, paints and cosmetics, among others. These chemicals are thought to be responsible for declining sperm counts and quality, genital malformations, retarded sexual development and increased incidences of certain types of cancer.

Since June 2008, there is an European agency on the control of chemicals: the European Chemicals Agency (ECHA). Located in Helsinki, ECHA is responsible for managing the implementation of the REACH requirements in relation to the registration, evaluation, authorisation and restriction processes of chemical substances.