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.
Leukemia and myeloma, which start in the bone marrow, and lymphoma, which starts in the lymphatic system, are the most common types of blood cancer. What causes these cancers is not known. As leukemia and myeloma grow within the bone marrow, they can interfere with the bone marrowâs ability to produce normal blood cells, including white blood cells, red blood cells, and platelets. This can cause frequent infections, anemia, and easy bruising.