Abstract: A device for detecting the presence of hazardous substances includes a support layer and a number of reagent media disposed at corresponding locations on a front surface of the support layer. Each of the reagent media exhibits (i) a known rest color when in a non-reactive state, and (ii) a reaction color different from the rest color when the media reacts with a certain hazardous substance. The reagent media are covered by a cover layer through which portions of the media are visible, and text indicia in proximity to a given reagent media identifies the hazardous substance with which the given media reacts. The rest color of a given reagent media is matched by corresponding color indicia located on the device in proximity to the given reagent media. Thus, one or more reacting reagent media can be identified by contrast of their reaction colors with the color indicia on the device.