Phthalates, or phthalate esters, are esters of Phthalic acid. They are used to dissolve raw materials when making fragrance oils. In order for a perfumist to be able to dissolve the powder and/or crystalline ingredients into liquid oil, he must use solvents. A common solvent that has been used for over 50 years is DEP (Di Ethyl Phthalate). This solvent has been declared as safe by even the most intense worldwide standards.