Data for this report was collected from other sources and forms of documentation as early as the day of the event. Information and details such as population sizes, weather conditions that day, human population distribution and more were all information collected from that day of the event. Other forms of data collected, ranging over the time of the event occurring to the publication time, include factors such as the quality of the air, water, animals and living conditions surrounding the plant. Human radiation levels and infection were also gathered, radiation levels of crops and much, much more were all statistics and data collected over roughly twenty year timespan that this report covers. This is actually one of the main driving points of the report, listed in the title "twenty years of experience." It compiles 20 years of research and findings into one large report.