The term “emerging threats” is used to define relatively new chemical substances such as fourth generation agents (FGAs) and pharmaceutical based agents (PBAs) which are extremely toxic at trace levels and have the capacity to be used for chemical attacks. Following the lethal use of an FGA in Salisbury, UK in 2018, the US Department of Health and Human Services published a safety awareness bulletin for on-scene responders about FGAs which noted that hazmat teams have limited detection capabilities for these substances. Indeed, their complexity requires an emerging detection approach which can identify an agent by name when needed to drive decon considerations (for FGAs) but also classify an agent by type when thousands of novel analogs can exist and evade a library-based approach (for PBAs). Learn how chemical agents have evolved since WWI into the FGAs and PBAs of today and how handheld mass spectrometry addresses the field detection problem using a combination of targeted libraries to identify threats by name and broader classification algorithms to detect threats which have been newly synthesized. Hands-on exercises will be conducted to illustrate scenarios such as trace residue detection on contaminated surfaces and post-event decon verification.