Aim: As a contribution to risk assessment, biomonitoring examinations are conducted to identify the internal exposure and to improve occupational safety and health in the decommissioning of explosives. Methods: 13 employees exposed to 2,4,6- trintrotoluene in two ammunition decommissioning facilities in North Rhine-Westphalia and 13 subjects of an unexposed reference group were examined before, during and after implementation of occupational safety and health measures. The concentrations of the TNT metabolite 4-amino-2,6-dinitrotoluene (4A26DNT) in urine were determined using a GC-MS-EI method and the concentrations of the haemoglobin adducts of 4A26DNT in blood were determined using a GC-MS-NCI method. Results: Initially observed extreme values of urinary 4A26DNT in the two-digit mg/l range and up to 4,476 ng haemoglobin adducts per litre blood continuously declined in the course of the study to the two-digit μg/l range and the three-digit ng/l range, respectively. Otherwise only few health-related effects (number of erythrocytes and reticulocytes in blood) depending on the level of internal exposure were observed. Conclusions: With the two advanced methods for dose and biochemical effect monitoring it is possible, even without the existence of any occupational exposure limits, to monitor exposure and hence achieve improved health protection. It would nevertheless be desirable for practical purposes to set an occupational exposure limit (BAT or BLW).