The US Environmental Protection Agency (USEPA) approved six methods using an expedited approval process, which accelerates the approval of laboratory test methods. These six methods include USEPA Method 524.3, Version 1.0, Mitchell Method M5271, Mitchell Method M5331, Orion Method AQ4500, Systea easy (1-Reagent), and Method ME355.01. USEPA Method 524.3, Version 1.0 is a gas chromatography/mass ... [Show full abstract] spectrometry (GC/MS) method for determining purgeable organic compounds in finished drinking waters. Mitchell Method M5271 uses laser nephelometry to measure turbidity in drinking water. Mitchell Method M5331 uses light-emitting diode (LED) nephelometry to measure turbidity in drinking water. Orion Method AQ4SOO uses LED nephelometry to measure turbidity in drinking water. Method ME355.01 uses direct headspace injection after acidification followed by GC/MS to determine the concentration of cyanide, as free cyanide, in drinking water.