Developed in response to the possibility of emission controls imposed by acid rain legislation, the Foster Wheeler limestone injection method can also be used in boilers that must fire low-sulfur coal to meet current emissions limits. Although it was originally designed strictly for NO//x control and has now been adapted to SO//2 reduction, the low-NO//x burner also has advantages unrelated to environmental protection. These include better flame stability and greater turn-down capability than older turbulent burners, complete flame shaping control, and less excess air.