Those who manufacture plastic explosives often use what to tag each batch?

The use of chemical markers for tagging batches of plastic explosives is a standard practice in ensuring traceability and detection. These markers are added to the explosive material during manufacture and serve as a distinguishing feature that law enforcement and security agencies can use to identify the source and authenticity of the explosives if found in criminal activities.

Chemical markers can be specific substances that do not alter the performance of the explosive but can be detected through various methods, such as chemical analysis, allowing authorities to link the explosives back to their manufacturer. This is crucial for preventing illegal use and for investigation purposes when explosives are used in crimes or terrorist activities.

In contrast, the other options listed do not serve a similar practical application in this context. Radioactive materials are not commonly used for tagging explosives due to safety and regulatory concerns. Fingerprinting techniques and biometric identifiers are more relevant in personal identification contexts rather than tracking batches of manufactured materials. Thus, the implementation of chemical markers represents a proactive approach in the broader field of homeland security and explosives management.