the who calculations using this model determined that the most at risk group, infants, who were in the most affected area, would experience an absolute increase in the risk of cancer(of all types) during their lifetime, of approximately 1% due to the accident. with the lifetime risk increase for thyroid cancer, due to the accident, for a female infant, in the most affected radiation location, being estimated to be one half of one percent [0.5%]. cancer risks for the unborn child are considered to be similar to those in 1 year old infants.