The mercury arc lamp has long been used as a light source for fluorescence microscopy. Almost every new research or clinical grade fluorescence microscope is equipped with a mercury arc lamp. However, mercury arc lamps are hazardous, consume a lot of energy, have a high cost of ownership and are unreliable. Metal halide doped mercury arc lamps have become widely employed because they address the reliability concerns around traditional mercury bulbs, increasing bulb longevity ten times. However, the cost of a metal halide bulb is typically about five times that of a mercury bulb of equivalent radiant power, offsetting much of the potential savings in bulb replacement costs. Ozone-free Xenon sources have no mercury, reducing the amount of hazardous waste, but they perform at a lower intensity. Solid-state technologies like LED illumination have the potential to solve all the concerns associated with the use of mercury, but LEDs alone have yet to achieve the brightness needed for microscopy. Thus, the use of mercury lamps has remained a necessary and wide-spread source of mercury in research laboratories for decades. Lumencor has overcome the frustration associated with this dependence on mercury and has revolutionized the solid-state technology world by manufacturing Light Engines capable of replicating and exceeding the spectral properties of the mercury arc lamp. In so doing, Lumencor has obviated the toxic disadvantages previously associated with microscopy. Light Engines allow scientists to utilize high-performance, solid-state, sustainable lighting solutions in clean, safe laboratories using mercury free microscopes.