Recently, two directors of HEAL wrote an article titled “Utah has already paid its price for America’s nuclear programs” (May 6). Let us carefully examine HEAL’s claims. Depleted uranium (DU) is a residual product remaining after uranium-235 and 234 have been effectively removed from natural uranium (U). This enriched U-235 product is used to produce nuclear fuel for U.S. nuclear reactors and highly enriched U-235 for nuclear weapons.

The first weapon applications was the 64 kg of U-235 in the “Fat Man” weapon (16 kilotons or kT) used at Hiroshima on Aug. 6, 1945, and the 6 kg plutonium (Pu-239) weapon (21 kT) on Aug. 9, 1945, used at Nagasaki. The immediate Japanese death toll from these two nuclear weapons was about 103,000. Interestingly, the total high explosive and incendiary bombings of Japan killed over 100,000 and had a total equivalent energy release of over 100 kT.

The amphibious landing by Allied forces in Okinawa resulted in 65,000 U.S. casualties, 77,000 Japanese military and about 100,000 civilian casualties. Okinawa was the bloodiest campaign in the Pacific, and Secretary of War Henry Stimson was concerned over the potential American casualties from the planned invasion of the Japanese homeland during “Operation Downfall.” A study by Quincy Wright and William Shockley estimated Allied casualties of between 1.7 and 4 million, with 400,000 and 800,000 deaths, and Japanese casualties from 5 to 10 million.

At the time the U.S. dropped its atomic bomb on Nagasaki, the Soviet Union launched a surprise attack with 1.6 million troops against the Kwantung (Japanese) Army in Manchuria. However, the threat of additional nuclear weapon use including a nuclear weapon to destroy the imperial palace and the emperor was an unacceptable risk that the Japanese military could not prevent. Significantly, the death of 5 to 10 million Japanese civilians was subordinate to the loss of Emperor Hirohito, who was regarded by the Japanese as their mortal God. It was only Hirohito’s public broadcast declaring unconditional surrender that finally ended the war for Allies and Japan.

In his 1955 memoirs, President Harry Truman stated that the atomic bomb probably saved half a million U.S. lives by avoiding the invasion of Japan planned for November 1945. Stimson later wrote of preventing 1 million U.S. casualties, and Churchill claimed saving 1 million Americans and half that number of British lives because of the atom bomb use.

Assuming 400,000 casualties among the Allies, projected casualties for Utah veterans for the mainland Japanese invasion was about 4,000. Remarkably, many of the World War II Utah veterans that Utah honored recently and sent to Washington would not have made the trip without the present U.S. inventory of DU. Is the controversial disposal of DU unacceptable payment in exchange for the lives of thousands of Utah veterans saved by these two atom bombs?

Depleted uranium exhibits about half of the activity of natural uranium because the shorter-lived isotopes of U-235 and U-234 are removed in the enrichment process. In about 2 million years, DU will return to its equilibrium condition found in nature. The claim that depleted uranium gets hotter over time is simply the fact that depleted uranium is returning to its natural state with the ingrowth of radioactive daughter products and approaching the level of radioactive emission of natural uranium.

Natural uranium occurs in all soils and in Utah soils at about 2 ppm. This amount of natural uranium distributed within the top 1 meter of Utah land represents three times the 700,000 metric tons of DU proposed for disposal. Furthermore, Utah’s natural uranium in surface soils is under homes, schools and churches and exhibits about twice the level of radioactivity of DU.

The state of Utah has expressed great concern about the impact this DU will have upon potential human radiation exposures in Utah. If the primary concern is the reduction of ionizing radiation exposure, then Utah and HEAL should first address medical applications of ionizing radiation, which contribute over half of the total U.S. background radiation exposure now (6.2 mSv was the total effective dose per U.S. person in 2006. Source: NCRP Report-160).

Radiation exposures from all U.S. nuclear industrial activities including nuclear power and waste disposal (including DU) is less than 0.2 percent of U.S. background exposure. Remarkably, the radioactivity from naturally occurring potassium-40 in a child’s lunch banana is greater than the activity from natural uranium in the same volume of Utah soil.

Gary M. Sandquist is professor emeritus of the University of Utah and a retired U.S. Navy commander.