This final rule amends the ``Guidelines Establishing Test Procedures for the Analysis of Pollutants'' under section 304(h) of the Clean Water Act by adding Method OIA-1677: Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry (hereafter Method OIA- 1677). Method OIA-1677 employs flow injection analysis (FIA) to measure ``available cyanide.'' Method OIA-1677 is an additional test procedure for measuring the same cyanide species as are measured by currently approved methods for cyanide amenable to chlorination (CATC). In some matrices, CATC methods are subject to test interferences. EPA is approving Method OIA-1677 because it is more specific for available cyanide, is more rapid, measures cyanide at lower concentrations, offers improved safety, reduces laboratory waste, and is more precise and accurate than currently approved CATC methods.