In the Ontario-Hydro Method (ASTM D6784-02) a sample is withdrawn from the flue gas stream isokinetically through probe/filter system, maintained at 120OC (250OF) or the flue gas temperature (whichever is greater), followed by a series of impingers in an ice bath. Particle-bound mercury is collected in the front half of the sampling train. Oxidized mercury is collected in impingers containing a chilled aqueous potassium chloride solution. Elemental mercury is collected in subsequent impingers (one impinger containing chilled aqueous acidic solution of hydrogen peroxide and three impingers containing chilled aqueous solutions of potassium permanganate). Samples are recovered, digested, and then analyzed for mercury using coldvapor atomic absorption (CVAAS) or fluorescence spectroscopy (CVAFS). The scope of the method applies to determination of elemental, oxidized, particlebound and total mercury emissions from coal-fired stationary sources with concentrations ranging from approximately .05 to 100 ug/dscm. The sample train configuration is similar to EPA Method 5.