Quest and Metrosonics have recalled their aq-5000 and aq-5001 Indoor Air Quality Monitors. Quest Technologies has discovered that a wiring error may have occurred during the production of some Metrosonics and Quest brand aq-5000 and aq-5001 Indoor Air Quality Monitors. This error may result in unstable sensor readings under certain circumstances. The potentially affected units have serial numbers whose last four digits are between 1760 and 2141, inclusive, and were shipped by Quest between September 29, 2000 and November 15, 2001. These unstable readings may be observed during normal operation or during calibration. The wiring error involves the reversal of two ground wires. The result of the wires being reversed is an increased instrument sensitivity to static electricity. Instruments operated in extremely dry air or by personnel carrying an electrostatic charge are likely to exhibit the described symptoms. The same instrument operated in higher humidity environments is not likely to exhibit these symptoms, but in either case the readings are suspect. Quest requests that all units within the identified serial number range be returned for immediate repair. Call 800/245-0779 for more details.