BlueDEF® is a mixture of 32.5% high purity synthetic urea and 67.5% deionized water that is used in Selective Catalytic Reduction(SCR) systems on diesel engines. DEF is the primary ingredient used to help convert NOx to harmless nitrogen and water. BlueDEF is stable, colorless, non-flammable, non-toxic and is classified as minimum risk for transportation. BlueDEF conforms to the ISO-22241-1 specification for DEF, is API registered and meets or exceeds OEM specifications. The shelf life of DEF is directly related to the temperature at which it is stored. Storage temperature between 12º and 86º F are recommended to maintain optimal shelf life of up to two years. If BlueDEF freezes, its efficacy will not be effected upon thawing. To maintain the purity of DEF and not harm the SCR Catalyst System care must be taken regarding the material of construction for all items that come in contact with the DEF solution. Included from the ISO-22241-1 standards are the recommended and not recommended materials for contact with DEF.