Chemical threat detection is a challenging problem. Contaminants must be accurately identified and quantified often in complex mixtures where non-toxic components can often obscure the measurement. Furthermore, highly toxic chemicals are problematic at low concentrations, requiring ultra-sensitive, real-time measurement methods to provide adequate warnings of dangerous environments. Improved public health and safety can be achieved by more effective chemical threat detection with improved sensitivity, accuracy, and reliability of the chemical detectors. This program addressed a wide variety of issues ranging from the chemical detector specifications and laboratory test methods to verify that commercial detectors meet manufacturer claims to low-cost field tests to verify that deployed detectors continue to operate. The program provides end users and government agencies with key decision tools for equipment procurement, equipment testing, and program planning to meet next generation needs.
NIST has developed standard specifications, test methods, reference data and reference methods to improve the evaluation of chemical detectors used by first responders. There are very limited numbers of reference materials that are appropriate for chemical detector testing and certification. The lack of reference materials is in part due to the reactive nature of the toxic industrial chemicals which makes it difficult and costly to deliver reference materials by conventional methods. Additionally, there is a great need to certify the detector performance under more realistic conditions where environmental interferents can impact the chemical measurements. As an alternative to reference materials, NIST has demonstrated that in-situ, optical probes are useful to directly monitor the test vapor streams in real-time, thus providing a mechanism to track the composition and concentrations of the test vapor streams at the chemical detectors while the detectors are under test. Additionally, NIST recently developed a Threshold Confidence Checker to provide a low-cost tool that enables end-users to verify that the M4 JCAD alarms at the original threshold level.