Women are exposed daily to D4 because it is used in numerous personal care products including hair sprays, lotions, antiperspirants and breast implants. The estimated average daily intake of D4 for a woman who used multiple products except breast implants is 0.158 mg/kg/day (11.1 mg/day). A physiologically- based pharmacokinetic (PBPK) model was developed to determine the bioavailability of D4 leached from saline filled silicone breast implants and after repeated inhalation exposures of D4 from personal products. The model was calibrated using previously published [14 C] D4 distribution studies as reported by Kirkpatrick et al (1996). The results were extrapolated to simulate multiple exposures of D4 in women by inhalation and breast implantation. The model was validated using published inhalation data in rats and humans. The kinetic results indicated accumulation of D4 in women more than men in various target tissues such as fat, liver and kidneys following single and repeated exposures by IV, inhalation and implant exposure. Due to its high lipid solubility (Log P oct/water = 5.1), D4 persisted in fat with a half- life of 11.1 days following inhalation and 18.2 days following breast implant exposure. For women exposed to both personal care products and breast implants, the accumulation of D4 in fatty tissues should play an important role in the risk assessment of breast implants.