[en] Contamination of working surfaces by radioactive dust is commonly monitored using surface wipes and liquid scintillation counting, or using gas flow counters alone. A careful examination of the radiological protection measures described here shows that they fail to meet international safety requirements for monitoring tritium contamination. These techniques now discredited, must be discontinued. Acceptable traceable contamination readings can be obtained using a direct-reading vacuum scintillation counter calibrated with a standard source. (UK)