Data Item No. 02016 provides both static and dynamic fracture toughness data for over 150 specifications of cast iron in the grey@ chilled@ white@ malleable@ ductile and compacted graphite forms. Also included are detailed descriptions of the general nature of these irons@ and their respective fracture characteristics. Additionally@ the factors likely to influence a measured fracture toughness value for a given material are considered@ as are the peculiarities experienced with fracture toughness testing of cast iron. The fracture toughness data appearing in the Item fall within the temperature ranges of interest for practical applications@ with the full brittle-to-ductile transition spectrum being considered for a number of ductile irons. The applicability of the Barsom Temperature Shift to static fracture toughness values for ductile iron is also investigated. The Item contains an in-depth statistical analysis@ offering the user two methods for obtaining a design allowable fracture toughness value with a prescribed level of confidence. The first method is the result of studies of the correlation between the fracture toughness of various forms of cast iron and other parameters: hardness (white and grey cast irons)@ tensile strength (grey cast iron)@ and temperature (ductile iron). The second method is based on the provision of mean fracture toughness values for each type of material@ from which design allowable values can be calculated. A worked example illustrates the implementation of these techniques@ and guidance is given on the applicability of each method. Standard requirements for cast iron compositions and mechanical properties are provided@ and discrepancies in cast iron fracture toughness measurements obtained through the use of different variants of a standard test procedure are considered.