Dr. Kocher has extensive experience in environmental health physics and assessments of dose and risk from exposure to ionizing radiation, involving the development and application of models and databases for assessing radiation doses to the public due to radionuclides in the environment and health risks due to exposure to different radiation types, and evaluations of dose and risk assessment models for regulatory and decision-making purposes.


Dr. Kocher was principal author of a study for The National Institute for Occupational Safety and Health (NIOSH) to evaluate dose and dose-rate effectiveness factors (DDREFs) for low-LET radiation. These DDREFs are 

incorporated into cancer risk models in the Interactive RadioEpidemiological Program (IREP). Dr. Kocher’s work on assessing the biological effectiveness of different radiation types and their uncertainties was an important contribution to the development of IREP.  He was also principal investigator for the Defense Threat Reduction Agency (DTRA) to develop improved models and methods of uncertainty analysis for use in dose reconstructions.


For several advisory groups for Federal agencies and committees of the National Academy of Sciences (NAS) and National Council on Radiation Protection and Measurements (NCRP), Dr. Kocher contributed to:

  • “A Review of the Dose Reconstruction Program of the Defense Threat Reduction Agency” [NAS report]
  • “Risk-Based Classification of Radioactive and Hazardous Chemical Wastes” (NCRP Report No. 139),
  • “Approaches to Risk Management in Remediation of Radioactively Contaminated Sites”          (NCRP Report No. 146)
  • “Performance Assessment of Near-Surface Disposal Facilities for Low-Level Radioactive Waste” (NCRP Report No. 152)
  • “A Graded Approach for Evaluating Radiation Doses to Aquatic and Terrestrial Biota”  [DOE]


Dr. Kocher has been a frequent consultant to the International Atomic Energy Agency on issues of radioactive and hazardous chemical waste management and protection of the environment.


E-mail Dr. Kocher at: dck@orrisk.com

David C. Kocher, Ph.D.

Senior Scientist