I think that even today few people are aware of one of the big risks that was taken by the United States during the war. There was no alternative; we had to take it. But it gave the handful who knew about it some bad hours. It grew out of the possibility that the Germans might use radioactive material to block the cross-channel attack of the Allied forces.
To cast back for a moment, it had begun to seem possible to us early in 1943 that the Germans could have progressed to the point where they might be able to use atomic bombs against us, or, more likely, against England. Although this possibility seemed extremely remote to me, a number of the senior scientists in the project disagreed. One even went so far as to urge that I should warn the American people in an official broadcast that the United States might be hit by an atomic bomb. Naturally, I was opposed to doing any such thing. What I thought more likely was that the Germans would use an ordinary explosive bomb containing radioactive material. If we were unable to neutralize the effects of such a weapon promptly, a major panic could easily sweep through the Allied countries.
However, as the plans for the invasion of Europe began to take form, we considered very seriously indeed the possibility that the Germans might lay down some kind of radioactive barrier along the invasion routes. We could not calculate with any certainty the likelihood of their doing this, for we were truly in the dark then about their progress in atomic development. It had always seemed to most of us that their best prospects lay in the use of plutonium, which would demand a much smaller industrial effort as well as considerably less in the way of time, critical equipment and materials than any other method—provided they were willing to ignore safety precautions. This I felt the Germans would do, for considering what we already knew of their treatment of their Jewish minority, we could only assume they would not hesitate to expose these same citizens to excessive radiation. Hitler and his ardent supporters, we felt, would consider this a proper use for an “inferior” group, quite apart from the saving in effort and materials and time. Moreover, we knew that in the course of developing the plutonium process the Germans were certain to discover that tremendous quantities of highly radioactive fission products would be produced in their reactors. It would be perfectly natural for them to think of using these to lay down a barrier through which ground troops could not pass without disastrous results.
At the request of the Military Policy Committee, a three-man group, Conant, Compton and Urey, assisted by other project members, had made a study of radioactive poisoning; and on the basis of their report we had ordered a supply of portable Geiger counters1 and were training a number of our personnel to use them.
It was an ugly prospect, and as D-Day in Europe approached, I had to make up my mind what action I should recommend with respect to the possibility that the Germans might use radioactive poisons. In reaching a decision, I sought the opinions of those I thought most capable of giving advice, but after their advice was all in, I was no better off than I had been in the beginning. This was a time when I was most appreciative of the sound counsel of Conant. He was never one to become unduly excited over the wild conjectures that the fertile minds of some of our people could produce, almost faster, it sometimes seemed, than we could disprove them—even to our own satisfaction, if not to theirs.
In any event, a decision had to be made. Would Eisenhower’s troops encounter radioactive poisons? Should he be warned of the possibility? To me, the answers were “No” and “Yes.” I saw General Marshall on March 23, and recommended that we send an officer to England to warn General Eisenhower of what he might be up against. At the same time, in accordance with my usual custom,2 I handed him a memorandum:
WAR DEPARTMENT
Office of the Chief of Engineers
Washington
22 March 1944
MEMORANDUM TO THE CHIEF OF STAFF
L. R. Groves
Major General, C.E
Incl:
Draft
The draft of the letter to General Eisenhower read as follows:
22 March 1944
General Dwight D. Eisenhower
Office of the Supreme Commander
Allied Expeditionary Forces
London, England
Dear General Eisenhower:
In order that your headquarters may be fully advised of certain materials which might be used against your Armies in a landing operation, I have directed Major A. V. Peterson, who will be in England on temporary duty in the near future, to report to your office and to acquaint you, or such officers of your staff as you may designate, with the problems involved. The matter is of the highest order of secrecy.
Faithfully yours,
Chief of Staff
The use of officer messengers on highly secret missions, carrying no papers or very limited ones, was common practice in the Manhattan Project. Before their departure, I always instructed them carefully, going into the background and reasons for their missions so that they could answer any pertinent questions they might be asked and thus be of maximum assistance to the people with whom they talked. Written messages would have been extremely complex and confusing to anyone not thoroughly acquainted with our scientific progress in the atomic field. Worst of all, the reader might have had doubts about exactly what was meant. Then, too, there was always the problem of security. Every written message increased the chances of disclosing information to outsiders.
Peterson’s mission was to inform Eisenhower that it was possible for the enemy to use radioactive poisons, but he was to emphasize our belief that they would not be used and that the invasion plans should be made accordingly. After he saw Eisenhower, he had longer discussions with Lieutenant General Walter Bedell Smith, the Chief of Staff, and other members of the SHAEF and ETOUSA staffs.
When he was asked if he could remain to help in preparing the necessary precautionary measures, although he was supposed to return at once, he said he could, and informed me by cable of his decision. During this period he talked with members of the Chemical Warfare Service, which was to use the Geiger counters, with the Signal Corps, which was to maintain and repair them, and with the Medical Corps, which had to be informed of the possibilities with which they might be confronted.
The Chief Surgeon, Major General Paul R. Hawley, issued two cover orders designed to insure that GHQ would be promptly alerted if the Germans did resort to radioactive warfare, but worded in such a way as to disguise the real nature of the danger. One order said that trouble had been experienced with fogging (which always results when film is exposed to radiation) on certain photographic and X-ray films and that if any such trouble was noted by troops in the field, an immediate report should be made, citing lot numbers, so that defective film could be withdrawn from use. The order is given below in full:
RESTRICTED
OFFICE OF THE CHIEF SURGEON
EUROPEAN THEATER OF OPERATIONS
APO 871
3 May 1944
ADMINISTRATIVE MEMO NO. 60
Subject: Report on Fogging or Blackening of Photographs or X-ray Film.
To: Surgeon, FUSAG,
Surgeons, FUSA and TUSA,
Surgeon, USSTAF,
Surgeons, All Base Sections,
Commanding Officers, All Hospitals.
By order of the Chief Surgeon:
J. H. McNinch
Colonel, Medical Corps
Executive Officer
The other order, which follows, was aimed at securing immediate reports in case any symptoms of radioactive exposure were discovered among the troops.
RESTRICTED
OFFICE OF THE CHIEF SURGEON
EUROPEAN THEATER OF OPERATIONS
APO 871
3 May 1944
ADMINISTRATIVE MEMO NO. 58
SUBJECT: Report of an Epidemic Disease.
To: Surgeon, FUSAG,
Surgeons, FUSA and TUSA,
Surgeon, USSTAF,
Surgeons, All Base Sections,
Commanding Officers, All Hospitals.
By order of the Chief Surgeon:
J. H. McNinch
Colonel, Medical Corps
Executive Officer
To avoid any possibility of a misunderstanding, General Eisenhower very wisely wrote the following letter to General Marshall:
Supreme Headquarters
ALLIED EXPEDITIONARY FORCE
Office of the Supreme Commander
11 May 1944
Dear General:
I have had a careful analysis made of the project which you instructed Major Arthur V. Peterson to explain to me. Since the Combined Chiefs of Staff have not brought this information officially to my notice, I have assumed that they consider, on the present available intelligence, that the enemy will not implement this project. Owing to the importance of maintaining secrecy to avoid a possible scare, I have passed this information to a very limited number of persons; moreover, I have not taken those precautionary steps which would be necessary adequately to counter enemy action of this nature.
The action taken by this Headquarters has been as follows:
I am writing in similar terms to General Ismay for the information of the British Chiefs of Staff.
Sincerely,
/s/ Dwight D. Eisenhower
General George C. Marshall
The Chief of Staff
The War Department
Washington, D. C,
As far as I know, General Marshall never told either the Combined Chiefs of Staff or the Joint Chiefs of Staff of the problem. From his discussion with Peterson, General Eisenhower evidently gained a very clear understanding of our views. When his letter arrived, I knew that our advice had been fully accepted and that nothing more could be done except to pray that we had not made a mistake. In making my recommendations, I was well aware I had assumed enormous responsibilities in connection with the invasion, and consequently, I was more than a bit relieved when the Allied troops made good their landing without any report of radioactive interference.
1 These were developed and manufactured by the Victoreen Instrument Company. A number of them were sent to England for use if needed. Others were placed in various locations in the United States.
2 I had adopted this practice to save his time. He did not retain these memoranda but handed them back to me after he had finished discussing them.