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National Museum of Nuclear Science & History

Harold E. Hoover’s Interview

Manhattan Project Locations:

Harold Hoover was a member of the Special Engineer Detachment during the Manhattan Project. He worked as a filter foreman at the Y-12 Plant, but his real job was in counterintelligence, to ensure no sabotage occurred. In this interview, he discusses life in the secret city of Oak Ridge, and how he met his wife, who was a contestant in a beauty pageant.

Date of Interview:
June 18, 2005
Location of the Interview:


Harold Hoover: My name is Harold E. Hoover, that’s H-O-O-V-E-R, commonly known as Hal, H-A-L.

Cindy Kelly: Why don’t you start by telling me how you got into the SED [Special Engineer Detachment]? How you happened to get into the SED, and then what you found when you got to Oak Ridge?

Hoover: All right. I was under the ASTP [Army Specialized Training Program] program. Prior to that I was with the Ordnance Department as a hand and shoulder weapons instructor. I got into the ASTP program and was sent to Penn State University under civil engineering, although I was a chemical engineer.

From Penn State University, I got orders to take off and head south. I didn’t realize that I was coming to Knoxville. The orders read “Chicago.” But somehow or other things got mixed up, and I came into Knoxville direct, as a G.I. in uniform. There were a couple of WACs [Women’s Army Corps] met me at the train station, took me out to the Army area. And then the orders were changed because I was supposed to have gone to Chicago and made a transition there into a civilian setup. 

So the WACs took me to the Hotel Farragut in downtown Knoxville, where I spent about two weeks changing over from G.I. clothes to civilian clothes, with a 4-F [registrant not acceptable for military service] card, and was sent out to Oak Ridge, to the Tennessee Eastman Corporation, to apply for a job.

I became a filter foreman at the Y-12 Plant. Of course, this had been arranged for about twelve to fifteen of us who were in the Counterintelligence Corps, to work as filter foremen in that project. Because back in the early parts of ’43, there had been a problem with the first unit that started, in which it shorted out and they had to shut it down.

At that time, they didn’t know whether it was sabotage, or whether it was a problem in construction, or maybe something with the constructing company might have left some metal or something in the oil cooling system that shorted out the track. So that developed a problem, and that’s when they set up our counterintelligence group to come in. That’s the reason why everything was kind of messed up at the beginning, on account of the urgency of it, to come in.

That’s where we spent the Army service, as filter foremen down at Y-12. The oil and water cooling systems were the very critical part of the operation because they had to maintain temperatures, and they had to keep foreign material out of the oil and out of the water. And so that’s how I spent my Army career, as a filter foreman.

Kelly: How did you like being in counterintelligence? Did that create some awkward moments?

Hoover: I don’t know. And to this day, I don’t know how in the world—I have never hit the lotto, but, by the same token, why I was picked out for some reason or other. In talking with the other men in the organization, our little organization, they could never figure out either why they were picked for this particular operation. Most of us were chemical engineers, and so that’s how we ended up there.

Kelly: Can you explain Y-12? Can you walk me through the interior?

Hoover: Yes. The buildings went by dash buildings. They had a fore-number and there was a dash for a Dash 1, Dash 2, Dash 3, and I was in Dash 5. In the first three buildings, they had two tracks horizontally built on the one level. In Dash 5, they doubled up; they had one track over top of the other track. They had the same operation, only there was a duplicate track, one above the other. These tracks, of course, were where the uranium ore was introduced and the electromagnetic current was introduced and under a vacuum, and that’s where they were reduced down to U-235. 

They had huge vacuum tubes because it had to be done in a vacuum, and the vacuum tubes were cooled by the water system. The tracks, the individual units all around the tracks, which were as large as a football field in length, and they were not a circle, but they were oblong in shape. They had the electrical controls up above and down below where all of the filtering systems, cooling systems, and what have you.

And all the filters in the water system and the oil system had to be changed periodically. As they became contaminated, the temperature would rise, and if it went up above a certain temperature, you had to shut the unit down.  Of course we didn’t want that, so we had a schedule in which we would continuously go around the track and change filters.

We perfected a system where we knew just about how long it would take for the temperature to rise. So we were able to do away with two shifts and we did it all in one shift, because we set up a schedule to change a certain number of filters around the track each day. That saved a lot of time and also saved a lot of money, because we were able to do with two crews. That is about it, as far as the operation.

Kelly: Was it upstairs that they had the control panels?

Hoover: Yes, they called them cubicles and they were up in the second story.

Kelly: Now, can you describe the cubicles? What did they look like?

Hoover: Well, they were just like an electronic control panel on a solid wall on the walkway, and girls were operating those. They would monitor the temperature and the direction of the magnetic arc. They were actually controlling the heart of the operation.

Kelly: Isn’t it surprising that they trusted girls with such responsibility?

Hoover: In my early days I thought so, but then, by the same token—

Kelly: Can you start again? Because they won’t hear my question.

Hoover: Yes, well I was just going to say that women are much more adaptable to that than men, because I worked for the Ordnance Department before I went into the service, and this plant made bullet cores for .30 caliber and .50 caliber machine guns. They [girls] were doing all the testing.

They could automatically do it without even thinking about it, with all of the gauges, and at the same time carry on conversations with neighbors. By the same token, if there was something wrong, they would just stop, because things were not rolling along the way they were. These girls could watch these dials and what have you and still be aware of what was going on around them. A man couldn’t do that. They kind of wander a bit.

But women are—this I learned from the Ordnance Department— that’s the reason why they used women as inspectors, because they could set up a routine, and they would follow it. If there was something just happened to be wrong, they would automatically, instinctively feel it and they could pick it out. So that is my theory as to why they were chosen as operators.

Kelly: This is Ed Westcott’s picture of the girls coming in to the plant gates, the Y-12 gate, just at the change of the shift. And you see, it’s all women. If we show this picture on the screen, can you kind of describe what’s happening there and make some comments on it?

Hoover: Well, they had the main gates of the plant and you had to exchange badges. You had to have a badge in order to get in, and so therefore everyone had to come through the same place, just like turnstiles. They had security guards there and you did have to have a—it was a photo ID badge, and everyone had to have one of those to get in. So everybody went in and out of the same area. When the shift was over, you did have a large outflux of people and also a large influx of employees going in and out.

Kelly: There’s a picture in this book, a picture of a little boy having his badge inspected. At what age did children have to have a badge?

Hoover: That I’m afraid I don’t know. 

Kelly: But children did have to have badges, is that right?

Hoover: Well, in order to get into the Oak Ridge townsite, or the Oak Ridge complex at all, everyone had to have a badge. They had to be identified, and if they didn’t have the badge, they couldn’t get in.

If you had a guest coming, a relative or a spouse, they could not get through the Oak Ridge main gate unless you had arranged for a pass for them to get there. That didn’t make any difference whether they had a husband inside, or a wife inside working, or what have you. They still couldn’t get in unless the individual inside had made arrangements for them to come in as a visitor, and then they got a visitor badge.

Kelly: Talking about husbands and wives, what was the social life like, especially for the thirteen thousand single people?

Hoover: Well, my understanding was that the average age at Oak Ridge, when it was at the peak of population, was around twenty-five years old. I believe the peak of the population was around seventy thousand or seventy-five thousand, if I’m not mistaken. It was the fifth largest city in the state of Tennessee.

They had social halls, cafeterias. They had dances. They had various places around the townsite—the west part of town, and the regular townsite was the original area. They had churches, of course, and they had socials at the churches. It was just like any regular city; the only thing was that everyone was very young.

Kelly: Looking back on it, do you remember when they announced that the war had ended? Now, that picture that Westcott had of the people holding up the newspapers that said, “War Ends.” What do you remember of that day?

Hoover: Well, one of the main things, as far as I was concerned, was the fact that we immediately received orders to put on our uniforms. Because we had been civilians, and from that point on, we wore uniforms.

While I was a civilian working there, we lived in dormitories. And immediately upon getting the order to put on my uniform, there was no more dormitory. I had to move into the Army barracks and the military detachment, as did the other fellows in our group. So our life as a civilian was over and we were back into the military routine.

Kelly: Complete with KP [kitchen patrol] and all that?

Hoover: Well no, I escaped that. [Laughter.] No KP.

Kelly: How many barracks were there? You were in the dormitories. Here’s a picture here—is that a picture of dormitories or barracks?

Hoover: These were dormitories. They had men’s dormitories and women’s dormitories. In my case, I had a roommate. I don’t know of any single rooms. I think they were all double rooms, to my recollection. All the fellows that were in our outfit lived in dormitories, not necessarily the same one, but other dormitories that were around the area.

Kelly: Were the beds bunk beds? Can you describe the room?

Hoover: It was not that fancy. There was a desk and a chair in it and then there were two bunks beds, one on either side of the room. You didn’t have your own private bath; you had a community bath and shower. They [the beds] were very comfortable. They were just wooden, similar to a wooden barracks, only with a little more plush to them.

Kelly: What about the barracks, then? You got sent back to that. What were some of the things you might have missed about the dormitories?

Hoover: Excuse me? Again?

Kelly: Was there a big difference between the barracks and the dorms?

Hoover: Well, you didn’t have the privacy in the barracks. Back into the Army life, you did not have a private room. There you were in a barracks, no partitions or anything like that. It was back to the old Army life.

Kelly: So how do you feel about having been part of this Manhattan Project?

Hoover: Of course, by being in this, I did not experience any of the battles throughout the world, in Europe or the Pacific Theater. I don’t know how I would have done if I’d been assigned to something else. As I said earlier, I did not know why I was chosen for this.

Having been a hand and shoulder weapons instructor in Aberdeen, Maryland, we had people come in from all units that had been in other areas of the war theater. If they were going to Africa or if they were going to Europe, or if they were going into the Japanese or the Pacific Theater, we would teach them how to use a particular type of weapon that they might face, like German Mausers, the differences in ammunition. So if they had an occasion that they did not have any of their own, and they might have to use some captured weapons and what have you, they would know how to use them.

Following that, I was set up to be a First Sergeant in an infantry outfit that was heading overseas. Before I could report to North Carolina to get that, I received orders to go to Georgetown University and, following Georgetown University, I was sent to Penn State.

Now, all of this turning around, I do not know the reasons why, or why the Army would do that, unless possibly the fact that I had an engineering background. They may have needed engineers at that time for this project. I never did find out why. But that was what changed my career, as far as a military man, from being in combat to being assigned to Oak Ridge.

Kelly: And after the war was over, you stayed in Oak Ridge. Is that right?

Hoover: Well, following the war, when I was discharged in February of 1946, I already had a job at Y-12, as a civilian, to come back after discharge at Fort McPherson, Georgia. I came back and worked in the final phase of the chemical lab at Y-12, in which we processed the final product prior to it going over to Los Alamos. I worked there for just about a year, up until the time that they closed down the operation. That was an interesting experience, too.

Kelly: When was that? When did they do that?

Hoover: I think they did that in about March of ’46. I mean, that’s when I started to work there. ’47 was when they closed it down. Of course, I got married in May of ’46. She was an Oak Ridge gal too, a Y-12 girl. She was from Oklahoma but we met at Oak Ridge.

Kelly: At one of the dances?

Hoover: No. I had known her personally for about a year, but she didn’t know me because I was a civilian and I had not put on my uniform yet. But she walked past my office every day, because she worked for the electrical department and she carried communications from the headquarters down to the various divisions in different departments. She drove one of the Army cars. She would pick up dignitaries at the railroad station or the airport, and bring them in and take them back. 

Following the war, and after I got my uniform on, they were having a beauty contest in Oak Ridge. The head of the personnel, she came to me and asked whether I could help in supplying G.I.s as escorts for the beauty contest contestants. I told her under one condition, that I knew that my future wife was going to be one of the contestants and I said I wanted to be her escort. Under those conditions, we would see what we could do about supplying a G.I., and we did. That’s how I got acquainted with her, and we got married then in May of ’46.

Kelly: And she was the runner-up of this?

Hoover: Yes, she was the runner-up.

Kelly: What was the name of her title?

Hoover: Miss Atomic Bomb. She was the first runner-up. And our pictures appeared on The New York Mirror, front page of The New York Mirror, the Knoxville News Sentinel, and the Oak Ridge Journal. She still has those pictures.

Kelly: So this is obviously after the bomb? In ’46, ’45?

Hoover: That was in ’45. That was immediately after the war was over.

Copyright 2015 The Atomic Heritage Foundation. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of the Atomic Heritage Foundation.