A system including at least one detector and a central station in two-way communication with the detector is provided. The detector can include an ambient condition sensing element, a motion sensor, control circuitry, and two-way communications hardware. The control circuitry can determine an alarm event based on a first signal received from the ambient condition sensing element and can transmit an alarm signal to the communications hardware during the alarm event. The control circuitry can also determine a man-down event based on a second signal received from the motion sensor and transmit a man-down alarm signal to the communications hardware during the man-down event. The two-way communications hardware can transmit at least one of the gas alarm signal and the man-down alarm signal to a remote location, and the two-way communications hardware can receive a status inquiry from the remote location.