Heat stroke is a serious risk to workers wearing hot protective clothing or who are involved in strenuous activity where heat and humidity challenge the body's ability to control its internal temperature. To combat this risk, Casella USA has introduced its Microtherm® heat stress monitor. This simple-to-use, handheld device displays in real-time the Wet Bulb Globe Temperature (WBGT) index which is the internationally recognized method of calculating heat stress. The WBGT data collected is then compared to reference values as defined by the ISO 7243 standard. Appropriate "work rest" regimes can be adopted in the work place or medical assistance undertaken. In the event WBGT levels reach dangerous levels the Microtherm will alert the technician with audible and visual alarms. The Microtherm calculates WBGT by means of three sensors that are manufactured to demanding BS 1904 and DIN 43760 accuracy standards. The sensors measure three Parameters: natural wet bulb temperature (tnw), globe temperature (tg) and air temperature (ta). These sensors can be mounted directly on the instrument itself or remotely positioned by cable up to 30 feet away. For workers in power stations, steel works, bakeries, glass manufacturing and other occupations where heat stroke is a shared threat, the new Microtherm is an essential life-safety device. Its large dot-matrix graphical LCD displays real-time changing values of WBGT indoors and outdoors to allow rapid decision making. It also features data-logging capabilities to record date and time, plus the measured and computed values. Logging intervals can be set from 30 seconds to one hour with results shown in either Fahrenheit or Celsius. Casella includes with the Microtherm a Microsoft® Windows® 32-bit PC software package (Win HSM) that provides an interface for data collection and analysis. The software produces graphical and tabular reports that can easily be imported into other applications. Summary and WBGT Heat Stress Index reports can also be generated.