| Free Metabolite | Urine (µg/L) | |||
| Mean (SD) | Median | N < LOD | % Free | |
| MnBP | 1.65 (2.2) | 0.98 | 12/70 | 4.0 |
| MEP | 39.94 (45.71) | 28.75 | 3/70 | 76.35 |
| MBzP | 0.06 (0.08) | 0.05 | 36/70 | 2.8 |
| MEHP | 0.53 (0.8) | 0.05 | 36/70 | 4.7 |
| MEHHP | 0.44 (0.3) | 0.44 | 0/70 | 4.8 |