This paper documents a case study about the effect of sand production on casing damage. Many wells were converted from production to water injection. Formation of precipitates across the injection interval required frequent well washing which inadvertently involved reducing the well pressure rapidly. Consequently, solids were released from the formation into the wells. The well washing and associated solids production went unnoticed for an unknown length of time until significant casing deformation was encountered during a recent workover. The significant solids production caused casing buckling near the perforation interval. It also activated a weak plane in the overburden, I causing further casing damage. This paper will present relevant field data and engineering analyses to support the above conclusions. Field measures to improve the casing's resistance against I the buckling are also described.