The U.S. Center for Disease Control (CDC) did not put much stock in the local media’s sensationalism. The following was excerpted from their official report on the uranium tailings spill:

• “The U.S. Centers for Disease Control (CDC), in cooperation with the Church Rock community, found no documented human consumption of river water. Six Navajo individuals most likely exposed to spill contaminants were selected by the CDC and tested at Los Alamos National Laboratory, where they were found to have amounts of radioactive material normally found in the human body.” Recommendation: No further action required.

• “No public, private or municipal wells producing water for domestic use or livestock watering were affected by the spill. Wells drawing water solely from sandstone or limestone aquifers probably will never be affected by spill contaminants.”

• “Based on limited testing conducted by the CDC, the additional radiation risk from consumption of local livestock is small. The risk is about the same as the increased risk from cosmic radiation incurred by moving from sea level to 5000 feet in elevation.”

• “Computer modeling identified inhalation as the most significant pathway of radiation exposure to man from the spill. However, sampling of airborne dust along the Puerco River in Gallup soon after the spill showed only background levels of radioactivity. Moreover, one year following the spill, radioactivity levels in Puerco River sediments were reduced significantly due to dilution with uncontaminated river sediments.”

The Church Rock incident had been reported upon in the “Journal of Health Physics” (July 1984: Vol 47, No. 1) in an article entitled, “The Assessment of Human Exposure to Radionuclides from a Uranium Mill Tailings Release and Mine Dewatering Effluent.” This report was authored by two staff members of the U.S. Center for Disease Control two staff members of the New Mexico Health and Environment Department and a staff member of the U.S. Environmental Protection Agency. Two powerful conclusions were reached in this report:

“A review of state and federal regulations that pertain to the ingestion doses calculated from the Church Rock data indicated that no exposure limits were exceeded by the spill, or through chronic exposure to mine dewatering effluent.”

“In light of the currently known cancer incidence and mortality risks associated with levels of radionuclides measured at Church Rock and Gallup, we conclude that the exposed populations are too small for investigators to detect increases in cancer mortality with acceptable levels of statistical power. In fact, it may be misleading to establish a (cancer) registry with the foreknowledge of low probability of detecting mortality increases.”