associated with absorbed dose in the thyroid per unit intake of 1311 was reported by Dunning (Du81). The uncertainty associated with the ratio of l3lrz dose to total thyroid dose comes from not knowing the true composition of the BRAVO fallout (see Ja64, Ph82) and from not knowing the true time of intake. We assigned the value of 0.7 for the relative standard deviation of this quantity. Since total dose was related to 1 through 4 above by either multiplication or division, the relative standard deviation for absorbed dose was taken as g = = (0.7)? + (0.7)° + (0.7)? + (0.7) =1.4. The relative standard deviation was estimated for risk based on the above values for O,/a, Op/b and O,/c. Thyroid absorbed dose, number of years at risk, and number of effects are related to risk by multiplication and division. The relative standard deviation in risk was calculated in a similar way as was done for absorbed dose. We estimate the mean and standard deviation of thyroid cancers per million person-gray-years at risk to be equal to 150 + 230 (1.5 + 2.3 cancers per million person-rad-years at risk). Our estimate of the nodule risk rate and standard deviation was 830 + 1200 nodules per million person~gray-years at risk (8.3 + 12 nodules per million person-rad~years at risk). - 67 =