In 2004, Dr. Javier Esteban (JE) was involved in the risk assessment of chemical substances as a Spanish national expert in the directives of Existing chemicals and Biocides. In 2007, JE combined the risk assessment activity with research on the alteration of the retinoid system by complex environmental mixtures, technical mixtures of PCBs, non-dioxin like PCB 180, TCDD and brominated flame retardants. Currently, JE is a lecturer of Toxicology at the Department of Applied Biology and researcher at the Institute of Bioengineering of the Miguel Hernández University of Elche, Spain.