For United States Military Standards, IEST-STD-CC1246 is the latest revision of MIL-STD-1246. This all came about in 1997, the Army Missile Command commissioned the Institute of Environmental Sciences and Technology (IEST) to revise and adopt MIL-STD-1246 as an industry standard as its usefulness had expanded far beyond military applications, and U.S. policy was requiring agencies to convert government standards to nongovernmental standards where practical.[1]
The updated standard was written because of a need to define quantitative cleanliness levels for products that included components and fluids. Levels were defined for both particulate and nonvolatile residue (NVR) molecular contaminants.