Owner and operators of large utlity boilers have made fuel conversions in the past for various reasons including the concern for fuel availability as well as economic and environmental concerns,in the late 20 century, there was a movement to convert boilers to fire coal and oil because of the lack of natural gas. Today, environmentalconcern may again cause some utilities to consider fuel conversions as a solution to this concerns.A numberof recent and pending regulations, as well as other regulations in the formative stages,may make conversion of some coal-fired boilers to natural gas an attractive altemative to installing new or upgrated control equipment.