A system includes one or more devices for providing information about a physical condition or environmental hazard. Each device includes a sensor physically associated with the user for detecting a predetermined environmental hazard and/or a physical condition of the user. The device is usually in the form of a wristband patch or tag attached to the user. The one or more sensors are adapted to detect predetermined chemicals, biological organisms, radiation or user blood pressure, heart rate, temperature, oxygen level, glucose level, skin condition, or biological and chemical changes of the user. An electronic circuit communicates with the sensor and includes an alarm for notifying the user or a third party of elevated environmental hazards or abnormal physical conditions of the user. Typically, the electronic circuit includes a transmitter, such as a radio frequency transmitter, for conveying information obtained from the sensor and electronic circuitry to a third party.