Table 1.
Distributions of benzene exposure measurements (air, urinary benzene, and urinary MA) among benzene-exposed and -unexposed workers.a
| Percentiles | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Exposure measurement | n | GM (GSD) | Minimum | 10th | 25th | 50th | 75th | 90th | Maximum | ||||||||||
| Urinary benzene (µg/L) | |||||||||||||||||||
| Unexposed | 11 | 0.1 | (1.3) | 0.1 | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 | 0.2 | |||||||||
| Exposedb | 30 | 14.9 | (5.0) | 0.8 | 2.4 | 4.3 | 11.0 | 59.0 | 120.5 | 617.0 | |||||||||
| Low exposed | 10 | 2.8 | (1.7) | 0.8 | 1.4 | 2.4 | 2.9 | 4.3 | 5.0 | 5.4 | |||||||||
| Moderate exposed | 10 | 11.6 | (1.6) | 6.7 | 7.0 | 7.2 | 11.0 | 21.0 | 21.3 | 21.3 | |||||||||
| High exposed | 10 | 102.4 | (2.1) | 48.5 | 49.2 | 59.0 | 110.6 | 123.1 | 373.9 | 617.0 | |||||||||
| Total | 41 | 4.1 | (12.8) | 0.1 | 0.1 | 0.2 | 5.4 | 21.3 | 114.9 | 617.0 | |||||||||
| Air (ppm) | |||||||||||||||||||
| Unexposed | 11 | — | < LOD | < LOD | < LOD | < LOD | < LOD | < LOD | < LOD | ||||||||||
| Exposedb,c | 30 | 2.8 | (3.6) | < LOD | 0.7 | 1.0 | 3.3 | 7.0 | 16.3 | 23.6 | |||||||||
| Low exposedc | 10 | 1.0 | (2.6) | < LOD | 0.3 | 0.7 | 1.2 | 2.1 | 3.1 | 4.1 | |||||||||
| Moderate exposed | 10 | 3.0 | (3.4) | 0.6 | 0.7 | 0.8 | 3.7 | 7.0 | 17.2 | 23.6 | |||||||||
| High exposed | 10 | 7.6 | (2.2) | 2.0 | 2.8 | 4.4 | 8.4 | 14.1 | 19.4 | 20.2 | |||||||||
| Totalc | 41 | 1.3 | (5.6) | < LOD | < LOD | < LOD | 1.3 | 4.7 | 11.6 | 23.6 | |||||||||
| Muconic acid (mg/L) | |||||||||||||||||||
| Unexposed | 0 | — | — | — | — | — | — | — | — | ||||||||||
| Exposedb | 30 | 5.3 | (3.3) | 0.8 | 1.2 | 1.9 | 6.6 | 13.8 | 25.2 | 40.9 | |||||||||
| Low exposed | 10 | 1.7 | (1.6) | 0.8 | 0.9 | 1.2 | 1.7 | 2.7 | 3.2 | 3.3 | |||||||||
| Moderate exposed | 10 | 5.4 | (3.1) | 1.1 | 1.3 | 1.9 | 7.9 | 14.4 | 19.1 | 23.7 | |||||||||
| High exposed | 10 | 15.6 | (1.8) | 6.5 | 7.6 | 11.2 | 13.4 | 26.6 | 34.0 | 40.9 | |||||||||
| Total | 30 | 5.3 | (3.3) | 0.8 | 1.2 | 1.9 | 6.6 | 13.8 | 25.2 | 40.9 | |||||||||
| —, not measured. aNumber of men (n), GM, GSD, percentiles, and range of concentrations (minimum, maximum) among men. Urine samples and personal air measurements were obtained from each man at two time points approximately 1 month apart, and the GMs of the paired measurements were used to calculate summary statistics. bExposure categories are based on tertiles of urinary benzene concentrations among exposed men (low: 0.8–5.4, moderate: 6.7–21.3, high: 48.5–617.0 µg/L). cTo estimate the GM and GSD, values < LOD (all 11 unexposed men and 1 low-exposed man) were imputed as LOD/√–2. | |||||||||||||||||||