Mono-n-butyl phthalate (MBP) is the major metabolite of dibutyl phthalate with proven estrogenicity. A TDI of 10 µg kg -1 body weight per day is defined for the parent compound (namely, 3.3 µg kg -1 body weight per day for infants), but not yet determined for the metabolite . Even if a similar TDI were assumed for MBP, our hUBI of 1.1 µg kg -1 body weight per day would not exceed this recommendation.