A method and an apparatus for detecting the release of a chemical, biological, or radiological agent are disclosed. In some embodiments, a microphone is used to continuously monitor sound and acquire acoustic data and a sensor is used to substantially continuously monitor a property that is related to a chemical, biological, or radiological agent. The acoustic data is analyzed for a signature that is distinguishable from background sound. The sensor data is analyzed for an event that is indicative of the release of a chemical, biological, or radiological agent. The acoustic signature, and the time at which it is observed, is used to corroborate the sensor data.