An environmentally responsible iron chelating additive and method for removing hydrogen sulfide or sulfide ions from drilling and packer fluids and preventing settling of precipitates. Iron chelating agents selected from the group consisting of ferrous lactate, ferrous gluconate, ferrous bis glycinate, ferrous citrate, ferrous acetate, ferrous fumarate, ferrous succinate, ferrous sacchrate, ferrous tartarate, ferrous glycine sulfate, ferrous glutamate, ferrous ascorbate, ferrous polymaltose, or a combination thereof, may be used. When the fluids are oil based, the iron chelating agents are added to the water phase of an emulsion, and the emulsion is added to the fluid. Viscosifiers may also be added to the drilling fluid with the emulsion.