TraceTek sensors DIRECTLY sense the materials being monitored at the sensor level without electromechanical components. Effectively, this is like having a sophisticated chemical lab positioned all along the sensor's length. And it works! TraceTek 3rd Party EPA testing by Carnage Mellon indicates a 100% chance of detection and a 0% chance of a false alarm for ALL TraceTek sensors. Additionally, Third Party Response Threshold Testing for the TraceTek hydrocarbon fuels sensor demonstrates a 25,000 - 50,000 ppm sensitivty to hydrocarbon liquid and vapor phase materials.