Distinguishing passive contamination from active cocaine consumption: assessing the occupational exposure of narcotics officers to cocaine (1997)

Hair analysis has been used in probationary and parole populations to monitor for cocaine use, but only in very limited settings or circumstances. Its wider adoption has been limited by questions regarding the ability to distinguish environmental contamination of hair via casual contact from actual ingestion. To evaluate this capability we sought to identify persons routinely exposed to cocaine, who were not cocaine users. Undercover narcotics officers engaged in cocaine-centered enforcement activities and evidence room clerks who have no history of cocaine use were identified as an appropriate example population. Thirty-six active undercover officers and four evidence technicians were asked to voluntarily submit hair samples for analysis. Additionally two cocaine contaminated (aqueous soaked), three negative control samples, and hair from a self-reported crack smoker were also blindly submitted to the testing laboratory. The hair samples were washed and after washing, enzyme digested. The wash solutions and hair digest were each analyzed for the presence of cocaine. The results indicate that nearly every person had trace amounts of cocaine contamination in the wash fraction, and one person had cocaine present in their hair digest. That person, when retested, was a negative. The laboratory correctly identified and characterized the contaminated, negative, and positive controls. The study concludes that the findings support the capability of hair analysis to distinguish cocaine use from exposure under normal field conditions. The study results indicate that cocaine-abstinent persons who are in chronic, casual environmental contact with cocaine are not likely to test hair positive for cocaine using the analysis protocols followed in this project. The study also indicates that passive microingestion of cocaine needs to be considered when examining persons who are in cocaine intensive environments.