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Mac and Vera Jo MacCready’s Interview – Part 1

Manhattan Project Locations:

W.K. MacCready received both his undergraduate and graduate degrees in physical chemistry from the University of Alabama. During the war, MacCready worked as a liaison between the construction and operations teams at Hanford, and later was a supervisor of the construction plant. In this interview, MacCready elaborates on the exceptionally fast building of the B-, T-, and U-Plants at Hanford, and his role as the construction and operations team manager. He describes his work with plutonium research, and the safety and secrecy associated with such research. He finishes the interview by elaborating on a fatal accident that occurred at the plant. Vera Jo MacCready was from Alabama, and traveled to Richland to join her husband in June 1944.

Date of Interview:
September 12, 1986
Location of the Interview:


W.K. MacCready: One of the challenging things we had, when we started up the separations plant and were running a reasonably complex chemical process, was that we were not able to inform our operators of the identity of any of the chemicals that they used, including the additives that they pumped out of the storage tanks and into the weigh tanks. They were Chemical Y, Chemical A and so on.

S. L. Sanger: So they wouldn’t even know that?

MacCready: They didn’t even know that. It was a little difficult to get the proper understanding and precautions into their minds, when they couldn’t know if it was sulfuric acid or sodium hydroxide.

Sanger: That’s what Wakie [Wakefield] Wright was saying, “You couldn’t explain it was radiation.” One of the things they had to worry about was to say, Just pay attention to what I say and don’t do what I tell you not to do.”

You came out here in which year?

MacCready: I actually arrived out here in mid-April of 1944. I joined the DuPont effort for the Manhattan District in Wilmington right after the first of the year, the second of January.

Sanger: Of ’44?

MacCready: Yes. I spent the time until I came out here, in a large degree, studying French. Another fellow by the name of Sam [Samuel] McNeight and I were chosen to become familiar with the design and to be out here and be a liaison between the operations folks and the construction folks.

Sanger: Now, are you a chemist?

MacCready: Yes, I graduated with a degree in chemistry.

Sanger: Then where did you go with DuPont?

MacCready: I graduated in the spring of ’35 and I went to DuPont in October of 1935.

Sanger: Okay. Your job out here then was mainly what, at the earlier stage?

MacCready: At the earliest stage, it was to become acquainted with the construction organization that was involved. I also was to be a source of information to construction about the things that were significant from the operation standpoint, questions that I might raise, information that I might give them in terms of answers to questions, when they had questions that related to things that the operating people thought were significant.

When I first got out here, the separations facilities were still in the stage where the buildings were being built. The buildings, of course as you know, were major chunks of concrete. There were some significant things from an operating standpoint. All the dimensions needed to be correct because they were significant to the ultimate operation. That was about all there was at that stage. So there were the two of us, Sam McNeight and myself.

Sanger: Keeping track of the dimensions?

MacCready: We would check that they matched, when they informed us of the dimensions. The two of us, one of us working in the East Area and one of us in the West Area, were able to take care of that all right.

Sanger: Which area were you in?

MacCready: I was in the West Area. At that time the East Area work, in terms of the concrete that we were talking about, was relatively far behind. But the East Area also had the major pipe works, where they were fabricating these close tolerance piping assemblies that would be used ultimately in the operating cells.

So Sam spent almost all of his time keeping track of the formation and the dimensional tolerances of those assemblies. Those were the ones that were going to be installed and removed remotely with cranes, so the dimensions on them were quite significantly important. Actually, they had a mockup, where they would seat and unseat by remote crane operation every one of them before they were ever shipped over for use.

Sanger: Every cell went through that mockup?

MacCready: Yes.

Sanger: Yeah, [Raymond P.] Genereaux mentioned that they did that remotely to make sure that they could do it.

MacCready: Yeah, if it would not work the whole system went to hell. The construction was going at a great pace. The first shovel that was stuck in the ground out here was in the early summer of 1943.

Sanger: At which one, the separation or the reactor?

MacCready: Neither one. The first shovel was stuck in the ground for either a rotor or a railroad.

MacCready: That first shovel was stuck in the ground in the early summer of 1943. All of the buildings, roads, railroads, and all of the interim structures necessary to carry on construction were built. The plant was finished and all of the temporary stuff was cleared out. Construction left by the sixth of February, 1945. Three reactors were built and three major separation plants. All of the affiliated stuff was built in less than two years.

Sanger: Yeah, that is amazing. When you got out to the separations area, what stage was that in? Were the walls up by then?

MacCready: Originally, we were going to build four separations plants. They decided at some stage before they got that far that three would be enough. So two of them were being built in the West Area and one was being built in the East Area. The one that was first was the T-Plant and it was about ten, twelve feet above ground at the time I got out here. The U-Plant at the other end in the West Area was just coming up to ground level.

Sanger: They were considerably below ground?

MacCready: Yes, the deepest cell was close to forty feet below ground level. They were still doing the excavation for the U-Plant at the time that I got here. I was here for the finish of T and U and all of the B-Plant in the East Area. The kind of thing that I talked about was relatively simple for the two of us to do.

The intent of DuPont was of course, as they did on all these kinds of plants, was to bring in operations people and have the whole operations crew here significantly before the plants were ready to operate. We were all particularly emphatic about doing that on this one. They started sending others of the separations crew starting in May.

As we came on and started getting more and more, when they got to the place where the concrete was finished and they were starting to put in the equipment that went with the cells, then there was a lot of activity going on all over the place. By then, by the end of June, we probably had twenty-five people here. I had those spread out. We had meetings every day and they got areas of activity that they looked after.

Sanger: They were keeping track of things, the way you were?

MacCready: Right. By the time the construction of T-Plant was finished, which was about October in 1944, we had probably eighty or ninety of the guys around. Things were staggered with the heavy emphasis on T, less on U, and still less on B. When T was finished, they heavied up on U and then so on.

As soon as T was finished and handed over to us, we skimmed off enough supervisors out of the review group to staff it. It was the same thing for the rest of them. When U was ready and was handed over to us, we skimmed a group off of them.

Sanger: U was in the East Area?

MacCready: No. 

Sanger: T and U were all in the West Area and B was in the East Area.

MacCready: Yeah. The old intent was that B and C would be in the East Area. C was never built. They did dig the hole, but that’s as far as it ever went. Along about the time that T was finished, we came to the conclusion from the research work going on all of this time that actually the output from the three reactors could be processed by two separations plants.

U was eighty-five percent finished at the time, so they went ahead and finished it. But the determination at that stage was that the two we would actually operate would be T and B. In those days, we did take a lot of precautions because we didn’t know—all of this process was designed on the basis of the work done in the laboratory with a few micrograms of plutonium.

We were going to put one in one area and one in the other. If we had trouble with one, it shouldn’t bother the other one if we put them that way. On the other hand, with T and U being closer together, if we had trouble it might make it impossible to use. 

Sanger: What were they talking about, what “trouble” might be?

MacCready: Trouble might be something about the process that didn’t function. There could have been radiation problems that would require heroic efforts and would not make it reasonable or feasible to work conveniently in that region.

Sanger: Was there a fear that there might be a concentration of plutonium of as it’d moved through the process?

MacCready: No, not at this time, and very properly so, because the phosphate process we used in those initial plants was a batch process.

Sanger: What does that mean?

MacCready: It means that you dissolved a batch of fuel and you ran that batch through the various steps throughout the plant as an entity. As against the continuous process, where you necessarily of course are keeping stuff available and feeding it in all the time and taking it off all the time. Then you’d have more reason to be concerned, because of the possibility that someplace things can accumulate that you’re not aware of. But with the batches and the process we had, where it went through tanks and through centrifuges and the like, it was pretty easy to run through flush systems for each batch and to be assured that the stuff was out.

Sanger: In other words, you’d run through one batch all the way through before you put another one in?

MacCready: No, the activities went on in the cells. You would never have more than one batch in a cell. Usually, in practical terms, because of the combination of timing on the fuel dissolving, you would have two or three cells between the succeeding batches. But nominally you could have had a different batch in each cell. There were usually two or three cells that were not functioning because it didn’t work out that way.

Sanger: How long would it take to run a batch through?

MacCready: It took around twelve hours.

Sanger: That’s all, huh. That’s through the T building?

MacCready: It was a two-stage affair. The T building had a 221 building. That was the big rascal, an eight hundred foot long job with heavy wall. Then there was a 224 building, which was next door. It was more of a normally designed building, mostly of concrete block.

By the time you ran through the T building, you had separated most all of the fission products, as well as the uranium from the plutonium, by the time you got to the 224 building. It was ninety-nine plus percent pure. That meant that the radiation exposure for it was very low. So it could run through the final stage of purification in sort of a normal building.

Sanger: You didn’t have to have all of the shielding.

MacCready: You didn’t have to have all of the shielding and you didn’t have all of the remote operating equipment.

Sanger: Was there another step after 224?

MacCready: Yeah. The product that came out of there was a 99.99 percent pure solution of plutonium in the form of a nitrate salt in a liquid form. That was taken to a building called 231. There at the first stage of activity, the plutonium was changed from the nitrate form to an oxide, a powdered form. That was put into a stainless steel carrier that was about so high and so big around. It had walls of thin steel, an inch and a half or so.

By that time, plutonium was only an alpha producer so a piece of paper would stop any radiation from it. There was no radiation concern about these carriers. Instead, it was more a security precaution, because they could fix them up and lock them up, if people stole them. You couldn’t get them open in a hurry. Then they were shipped off down to Los Alamos.

Sanger: So when it left here, it was in an oxide form?

MacCready: In those early days. Yes.

Sanger: Powdery?

MacCready: Yeah.

Sanger: But when it came out of the T building, what did it look like?

MacCready: Coming out of the T building, it was in a liquid nitrate form.

Sanger: Was it kind of syrupy?

MacCready: No, it was much more dilute than that. The stuff that came into 224 or 221 was probably no more than a one percent solution. When it came out of 224 going to 231, it was probably a fifteen or twenty percent solution.

Sanger: So it was a little thicker, then?

MacCready: Yeah. You wouldn’t be able to notice the difference, but it had a higher content. Since the stuff is readily soluble in nitric acid, the difference in appearance that you can see would not be visible just looking at it. It just gave it a more convenient volume to take down there. Their job down there was to get it out of solution and then into the oxide form.

Sanger: And that was almost pure, then?

MacCready: Yeah, that would have been a 99.99 plus plutonium oxide.

Sanger: And that’s how it went to Los Alamos in those days?

MacCready: Right. They started their job by changing that oxide into the metal form, and then taking the metal and casting it into the physical form.

Sanger: Another person that I talked to on that trip was Cyril Smith, who was a metallurgist at Los Alamos. Or I guess he was in charge of the metallurgic part of it. He talked about when he saw it, it was a fluoride. It was in a powdered form.

MacCready: In those days, there was a fluoride.

Sanger: He didn’t see it. When it came in originally, he said that other people dealt with it. They’re not necessarily people that know what they’re talking about, but mostly people talk about a syrupy form, at least before it left here. But syrupy could all be in the eye of the beholder.

MacCready: It would depend on some of the people that worked at 231 who would think of that, because there would have been a stage when they were going from the nitrate to oxide. The first thing they would do down there would be to boil off excess water. So they would have gotten it down to what would have looked like a syrupy form, before they went into the process activities to change the nitrate form into the oxide form.

Sanger: And that’s at the 231. What was that called?

MacCready:   In the early days they were all called just by the numbers. As long as 231 carried out that function, it didn’t have any other name. Later on, quite some years later, some of the steps that had been carried on at Los Alamos were moved to here and to Savannah River. The product that came out of the final stage came out of a building called 234-5, in those days. That was in a metal form.

Sanger: Oh, I see. It was never metal here, during the war?

MacCready: No, it was not. When it got to the place where we had that step, it was called the Metal Fabrication.

Sanger: It seemed like I’ve read something about either an isolation building or a purification or concentration. Those names seemed like they cropped up occasionally.

MacCready: There may have been some people in the process chemistry groups that thought in those terms. If that was the case, they were probably relating to the activities in 221, 224.

Sanger: At which point did the separation part of it turn it over to the Army? Was that when it came out of that final oxide?

MacCready: Yeah, it was kept at the 231 building until the Army was ready to make a shipment run. Then their people would come down and they would take possession of these containers of this stuff. They would sign all of the papers and put it in whatever means of transportation they were using at the time and take off with it. So that was when it first physically came into the possession of somebody other than a DuPont employee.

Sanger: Would they store it for a time at the Magazine Storage Facility?

MacCready: It was intended that that would happen. But in those early days, though, they wanted it badly enough that they skipped that step.

Sanger: A little later I think they did that.

MacCready: Yeah, once the war was over all of those kinds of pressures relaxed.

Sanger: After the process of the separation plants, what were you doing then?

MacCready: When we got all three of the plants and all of the affiliated buildings in the two areas built, that meant that the tail-end of B—I had accepted the B-Plant construction for operation— was done. Then I put on another hat and became the Assistant Chief Supervisor of the B-Plant in Operations. Sometime within the next year, the Chief Supervisor there moved up and became the S-Department Superintendent and I became Chief Supervisor of B.

Sanger: Was the War still on then?

MacCready: Yes, this was in the period while DuPont still there. It was in February that we started the business of the shake-down runs in the B-plant. That was when I assumed the Chief’s job. It was kind of interesting in this regard, remembering the basic knowledge that everybody had as a background for the development of the processes, the designs of some of these constructions. For the two separations plants that were starting up and actually used, in each case we took thirty days to run them through their shake-down activities and then they went into service. Now you can’t even unlock the damn front door in under six months.

Sanger: When you were going through the shake-down, what were you putting through them?

MacCready: The first thing we did was to run water through everything. That was to see that all of the valves and all of the pumps and all of the instruments did the things that they were supposed to do. After that, we ran an acid run through to check the same thing plus to see to it that there weren’t any places where acid versus water would cause leaks inside. After that, we were then in a position to start bringing in material and to process it through.

Sanger: Did you have any problems at first, or not of any serious nature?

MacCready: We had no problems of any serious nature. As I have said many times, by a combination of circumstances in the period from the time I started with DuPont until I came out here, which was about a matter of nine years, I had been involved with this liaison with the construction and the start-up of about fifteen plants. None of those plants, relatively small and simple by comparison, started up as easily and in such a trouble-free fashion and as quickly as these out here did.

Sanger: Why do you suppose that was?

MacCready: I think although the amount of specific information was limited, the amount of general information about the chemical processes and chemical plants that were involved with this assembly to people was very, very large. They were impressed with the significance of the fact that they were going a long way on very little information.

Everything as we went along was most carefully checked. Everything from fabrication on out, every step was very carefully checked and double-checked. I’m sure, as a consequence, we probably put more time, thought, and effort into every stage of things up to starting it up than we had ever done on any normal peacetime plant that any of us had been involved with. The consequence was that there was essentially nothing that hadn’t been accounted for before the event.

Sanger: All this in spite of the speed that you were working at?

MacCready: Right, yeah.

Sanger: What were the other plants that you were involved in? Is that in here?

MacCready: No, I was involved with a sodium sulphate recovery plant and an ethyl chloride plant, an acid recovery plant and, associated with that, a hydrochloride plant. Then there was a group of plants for making the plastics explosives in Indiana, where we had about twelve there.

Sanger: Is that the Indiana Ordnance?

MacCready: It was the Wabash ordnance groups.

Sanger: That’s where you were before you came out here?

MacCready: I was at the DuPont Chambers Works. From there, I spent six months in training school for the Wabash Ordnance Works. Then we got that started up and running in about a month or six weeks, when I got transferred back to the Dye Works because they were having trouble with their ethyl chloride plant.

Vera Jo MacCready: That’s the closest we ever came to a divorce.

MacCready: We didn’t want to go back there.

Vera Jo MacCready: No.

MacCready: But we did go back, but I did make it known that I didn’t want to stay. It was a year just after I went back that I was moved into the Manhattan District activity.

Sanger: What did they tell you when that happened?

MacCready: My boss at the Dye Works said, “There’s a chance for a job in another place and in another activity. You’d go over to Wilmington and see this guy in this office next Monday morning, and he will talk with you about it to see whether or not you’re interested.” 

When I did that, they told me. So I assume everyone who came in to thing at that stage were told. They told me what it was all about.

Sanger: What did they say? Do you remember?

MacCready: They gave a quick summary of the technical aspects of the thing and the fact that there wasn’t enough information from that to consider that it was possible to make atomic weapons. And that was the job that we were going to do. There were several facets to the program, as it were. There were two different types of approaches to enriching uranium down at Oak Ridge, as well as the plutonium approach. Then he went on and said that ours was going to be associated with the plutonium branch.

Sanger: Was that just one person talking to you, or was he talking to a group?

MacCready: I came in and on that day there was nobody else was coming in. I suspect that was largely true because, at the time, there were only about twenty-five or thirty in this particular group.

Most of us were what you might call “assisting hands” for the top design group that was headquartered there in Wilmington. We were gathering pieces of information for them, and also we were studying the material having to do with the concepts and the approach that they were proposing to take. We were educating ourselves a part of the time and then being flunkies for the design group the other part of the time.

Sanger: You would have been how old then?

MacCready: That was in January of 1944, so I was thirty-one.

Sanger: That’s when you first got into the Manhattan District?

MacCready: Yeah.

Sanger: Did they impress upon you that it was secret?

MacCready: Oh yeah. They impressed upon us that it was secret. We were not to tell nobody nothing. That included family.

Sanger: Was that generally followed?

MacCready: Yes, that was followed. That was totally followed until the announcement came out in the paper that the bomb was dropped.

Sanger: Yeah, that is amazing, isn’t it, that people would keep their mouths shut?

MacCready: Uh-huh, they did. Knowing the things that can happen and the number of people that were involved, it is amazing. When we were building the plant, there were only two people in construction that knew what they were building. They were the two top DuPont construction managers.

Sanger: [Gil] Church?

MacCready: Church and T. L. Pierce. There was nobody else in construction to my knowledge knew what they were building.

Sanger: Do you recall an accident during the chemical plant construction involving storage tanks, waste tanks?

MacCready: Yeah, I’d forgotten.

Sanger: It’s not a big part of it. It’s been hard to track it down. People talked about it, but they tend to disagree in their details.

MacCready: The thing happened a month or so, as I recall, before I got here.

Sanger: Oh, it did? So that would have been early ’44?

MacCready: Yeah. These were underground storage tanks for waste. The way that they built them, they would cut and shape chunks of them that were of a size that you could manhandle around with equipment to get it into place. Then they would put them together by welding. In order to do that of course, you had to have the thing so that you could weld on both sides, which meant it had to be supported up.

Sanger: Elevated.

MacCready: Elevated so that the people could get under there and weld. They had a wooden cradle thing, which the bottom of the thing sat in. As I understand it, the welding went on, and there was never but the one story that I heard.

They were welding underneath a part of this particular tank—and this is by no means sure— and I think there were three main people that were involved. Somehow or other the cradle either shifted or in some fashion in essence it collapsed, and those three people that were under there welding were crushed to death.

Sanger: Yeah, that’s what I’ve heard, except that the estimates of the fatalities went all the way up to seven. One of them was five, from this Monsignor [William] Sweeney, who is still in Richland.

MacCready: On that I don’t think I remember well enough.

Sanger: That’s a good description though of what happened, because nobody that I talked to was actually there. That was a subcontractor, I suppose.

MacCready: Yeah. It was a three-part group of subcontractors and I can’t remember their name now. Most of them were out of Idaho or Utah.

Sanger: Do you know of any other major accidents like that during the construction phase?

MacCready: With respect to the separation areas, I don’t recall any accidents after I got here through the construction that resulted in a fatality. It was not encouraged that people roam around, point one. Point two was that you were too damn busy to roam around.

So I don’t really know what was going on in other areas. Quite possibly if anything did go on you would not hear about them, because once again as a part of the business people around here did not reveal things or talk about their jobs.

Sanger: That must have been unusual.

MacCready: It was unusual.

Vera Jo MacCready: That was very unusual. We couldn’t even get our husbands to come into the living room to talk to the women.

Sanger: I understand in some parts of the world that’s considered bad taste, to talk about your work.

MacCready: Maybe. But as you know in this country—bad taste or not— it sure as hell goes on.

Vera Jo Macready: It sure does.

MacCready: I am sure that there probably were some other fatalities, but I don’t recall any of them. If there were, I’d suspect they probably were related more likely to some of the side activities rather than at the plant.

Sanger: Yeah, there were a number of auto accidents, drunk driving and homicides in the construction camps.

MacCready: Yeah, those were a part of the business of running a sizable construction camp.

Sanger: DuPont history mentions oddly enough just two fatalities. One of them was in the city when Richland was built. I forget where the other one was. They were subcontractors. Apparently DuPont didn’t have any fatalities.

MacCready: They subcontracted out most all of these sites that were not precisely pertinent to the process like the tanks, the railroads, the roads, the electrical lines. All of that kind of stuff they subcontracted.

Sanger: Of course you had to know what was going on, didn’t you?

MacCready: All of our supervisory team in separations were informed, as I was, from the time they were brought aboard. We could not tell our operators some of these special problems in terms of educating them to operate the chemical processes, and to handle chemicals safely without knowing what the hell they were.

Sanger: The idea being on that is that somebody was afraid that if you knew what the chemicals were, somebody might put everything together.

MacCready: Two or three pieces of information of that sort put together could mean something to people who had a background in the sciences. Because the operators, if you told them, would not have this degree of understanding, it was feared that they would be more likely to mention things of that sort without any thought that it had any significance. The easy way that was determined, if you didn’t provide them with information, that they couldn’t be careless with it.

Vera Jo MacCready: It was amazing how that was kept secret.

Sanger: I know. Apparently everybody agrees that nobody talked about it.

Vera Jo MacCready: No, they didn’t.

MacCready: I think by now there would have been some indications of it.

Sanger: It’s funny that there wasn’t more known about this place, because it was so huge and many people came and went here. Of course, there were lots of big war plants.

MacCready: There were lots of big war plants, so that was exciting. There was a sizable Naval Air Station here before this came on. 

Copyright 1989 S. L. Sanger. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of S. L. Sanger.