The failure of the dams came as a big surprise. Johnstown had constructed an entire system designed to completely eliminate the flood risk. In addition, regular inspections had turned up no defects. Still, the dams were no match for the thunderstorm that stalled over the area on July 20.
Common types of blood cancer include: 1  Leukemia: Cancer that originates in blood-forming tissue. 2  Non-Hodgkin lymphoma: Cancer that develops in the lymphatic system from cells called lymphocytes, a type of white blood cell that helps the body fight infections. Non-Hodgkin lymphoma: Cancer that develops in the lymphatic system from cells called lymphocytes, a type of white blood cell that helps the body fight infections. 2  Hodgkin lymphoma: Cancer that develops in the lymphatic system from cells called lymphocytes.
The exact cause of blood cancer is not known. Some types of blood cancer are due to spontaneous (not inherited) mutations in the genes that control production of specific types of blood cells. Immunocompromised people and people with autoimmune diseases have an increased risk of developing certain types of blood cancer.