In May of 2002, NIOSH published 42 CFR Part 82, Methods for Conducting Dose Reconstructions Under the Energy Employees Occupational Illness Compensation Program Act (EEOICP A) of 2000. These methods are being used by the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC) to conduct dose reconstructions for covered employees seeking compensation for cancer, other than as a member of the Special Exposure Cohort, under EEOICP A. The rule provides guidance as to how dose reconstructions are conducted to characterize the radiation environment to which workers were exposed. A hierarchy of methods is used, depending on the nature of the exposure conditions and the type, quality, and completeness of data available to characterize the environment. The methods employed are based on approaches similar to that used in traditional occupational dosimetry, but achieve efficiency by substituting scientific, reasonable, and fair assumptions in the place of extensive data collection. This allows for an increase in claims processing efficiency, which is essential for an effective compensation program, without compromising the accuracy of the final compensation decision.