Whole blood silicon levels in 30 patients with silicon-gel implants (inserted between 1973 and 1991) were compared with those of 24 healthy, age-matched, female patients without breast implants using atomic absorption spectrometry with a graphite furnace. The blood silicon levels in the implant patients were significantly higher than those of controls (medians 33.45 vs 17.05 ng/ml; p = 0.005). Of the 30 patients with implants, 15 had received their implants between 1973 and 1985, and 15 had received implants between 1986 and 1991. Implants made between 1973 and 1985 have been shown to be weaker and to have higher silicone "bleed" levels than those made from 1986 onward. However, there were no significant differences in the blood silicone levels between these two groups of patients.