Benzyl butyl phthalate (BBP) is an organic compound historically used a plasticizer, but which has now been largely phased out due to health concerns. It is a phthalate ester of containing benzyl alcohol, and n-butanol tail groups. Like most phthalates, BBP is non-volatile and remains liquid over a wide range of temperatures. It was mostly used as a plasticizer for PVC, but was also a common plasticizer for PVCA and PVB. BBP is classified as toxic by the European Chemical Bureau (ECB) and hence its use in Europe has declined rapidly.