Hugh Pickens writes "Science Daily reports that Homeland Security's Science and Technology Directorate's Cell-All is an initiative to equip cell phones with a sensor capable of detecting deadly chemicals. A chip costing less than a dollar would be embedded in cell phones and programmed to alert either the cell phone carrier to the presence of toxic chemicals in the air, and/or a central station that can monitor how many alerts in an area are being received. While one alert might be a false positive, hundreds would indicate the need for evacuation. 'Our goal is to create a lightweight, cost-effective, power-efficient solution,' says Stephen Dennis, Cell-All's program manager. Does this always-on surveillance mean that the govenment can track your precise whereabouts whenever it wants? On the contrary, DHS says; Cell-All will operate only on an opt-in basis and will transmit data anonymously."