Skip to main content

Search the Special Collections and Archives Portal

Interview with Robert Elmer Friedrichs, February 25, 2005


Download nts_000051.pdf (application/pdf; 3.58 MB)





Narrator affiliation: Radiation Safety, Reynolds Electrical and Engineering Company (REECo); Sr. Scientific Adviser, National Nuclear Security Administration (NNSA)

Digital ID


Physical Identifier



Friedrichs, Robert Elmer. Interview, 2005 February 25. MS-00818. [Transcript]. Oral History Research Center, Special Collections and Archives, University Libraries, University of Nevada, Las Vegas. Las Vegas, Nevada.


This material is made available to facilitate private study, scholarship, or research. It may be protected by copyright, trademark, privacy, publicity rights, or other interests not owned by UNLV. Users are responsible for determining whether permissions are necessary from rights owners for any intended use and for obtaining all required permissions. Acknowledgement of the UNLV University Libraries is requested. For more information, please see the UNLV Special Collections policies on reproduction and use ( or contact us at

Standardized Rights Statement

Digital Provenance

Original archival records created digitally

Date Digitized



32 pages





Nevada Test Site Oral History Project University of Nevada, Las Vegas Interview with Robert Friedrichs February 25, 2005 Las Vegas, Nevada Interview Conducted By Mary Palevsky © 2007 by UNLV Libraries Oral history is a method of collecting historical information through recorded interviews conducted by an interviewer/ researcher with an interviewee/ narrator who possesses firsthand knowledge of historically significant events. The goal is to create an archive which adds relevant material to the existing historical record. Oral history recordings and transcripts are primary source material and do not represent the final, verified, or complete narrative of the events under discussion. Rather, oral history is a spoken remembrance or dialogue, reflecting the interviewee’s memories, points of view and personal opinions about events in response to the interviewer’s specific questions. Oral history interviews document each interviewee’s personal engagement with the history in question. They are unique records, reflecting the particular meaning the interviewee draws from her/ his individual life experience. Produced by: The Nevada Test Site Oral History Project Departments of History and Sociology University of Nevada, Las Vegas, 89154- 5020 Director and Editor Mary Palevsky Principal Investigators Robert Futrell, Dept. of Sociology Andrew Kirk, Dept. of History The material in the Nevada Test Site Oral History Project archive is based upon work supported by the U. S. Dept. of Energy under award number DEFG52- 03NV99203 and the U. S. Dept. of Education under award number P116Z040093. Any opinions, findings, and conclusions or recommendations expressed in these recordings and transcripts are those of project participants— oral history interviewees and/ or oral history interviewers— and do not necessarily reflect the views of the U. S. Department of Energy or the U. S. Department of Education. UNLV Nevada Test Site Oral History Project 1 Interview with Robert Friedrichs February 25, 2005 Conducted by Mary Palevsky Table of Contents Introduction: reflections on Baneberry 1 Role of Analytical Radiological Laboratory ( RADSAFE): decontamination and monitoring of workers, analysis of samples 2 “ Hectic” mood at the NTS after Baneberry 7 Speculation as to cause of Baneberry venting, institution of Containment Evaluation Panel as a result of Baneberry 8 Work as Dosimetry Liaison Officer 9 Recalls Baneberry as a “ key memory” in career 11 Baneberry lawsuits 12 Talks about investigation of flight testing of magnesium aircraft in southern Nevada ( 1940s), artifacts remaining, and need for historic preservation 14 Details research on Cold War- era artifacts and icons, especially photograph of Miss Atomic Bomb ( 1950s) 18 UNLV Nevada Test Site Oral History Project 1 Interview with Robert Friedrichs February 25, 2005 in Las Vegas, NV Conducted by Mary Palevsky [ 00: 00: 00] Begin Track 2, Disc 1. Mary Palevsky: So, Robert, as I was just saying, I thought it would be useful if you could talk about some of your reflections about Baneberry. I was mentioning that there are certain events and images of the [ Nevada] test site that seem to stand out on the historical timeline, and Baneberry’s one of them, and you were involved in that. We have talked about it before, but maybe you can give me some of your reflections on it. Robert Friedrichs: Let me start with driving towards the front gate and seeing the cloud over the mountain. Absolutely no doubt that something had happened. You were coming from town? Yes. Were you in the car or in the bus? In private car. In a carpool at that point. And so we knew something had gone on. And we got in to the laboratory about fifteen minutes before eight. And again, at that time, work went from eight to 4: 30 and half- hour off for lunch and we worked five days a week. So it wasn’t like today where they work ten- hour shifts, four days a week. We got in. We found out immediately that there had been a venting. They were evacuating people from the forward areas. And so we knew we were going to be busy, so we immediately got a shopping list, went over to the warehouse, pulled out all of the disposable- type supplies that we would go through so that we had them there; we wouldn’t have to worry about getting them later. Nalgene bottles, various other items that were disposable. Got set up, had everything ready to go, and then essentially just tracked the information as it came through, made sure all of the calibrations were current, all of the UNLV Nevada Test Site Oral History Project 2 instrumentation was working. And then it took quite a while, but there finally was a bus that arrived full of people that had been contaminated. They had been taken to the control point [ CP], decontaminated there, or attempts were made to decontaminate them, and they had not been able to wash everything off, but they had pumped literally hundreds of people through there that day. They had no hot water— they simply overwhelmed the capacity to have or generate hot water – and so people were taking ice- cold showers in the middle of the winter, and they weren’t very fond of that. So they brought the busload down to the laboratory and we would bring them in, one at a time. They were wearing paper or anti- contamination coveralls and their clothes had already been taken at the control point. We would walk them through, get a urine sample, a thyroid count, a whole body count, and try to capture the amount of activity that remained after they went through another shower in our building where, in every case, with hot water and soap, they were able to get rid of the contamination on their skin— outside contamination. Just to back up a little bit about the day, for this recording, tell me again the name of your group, the name of your division or whatever we call it, so that we have that on this. Well, the popular term was the RADSAFE [ Radiological Safety] Group, but we were the Analytical Radiological Laboratory portion of that. And then there were the field monitoring group. We had other smaller groups besides that: a training group, instrumentation group. We had our professionals: our industrial hygienists, our health physicists, that were somewhat autonomous. But we were the Analytical Laboratory group. Then one other question about the buildup to when people arrive. Are you in radio contact or telephone contact with people out near the accident or at the control point about when people are going to be arriving or are you—? UNLV Nevada Test Site Oral History Project 3 [ 00: 05: 00] We got a series of telephone calls. We did not have radios in the laboratory. They were in Mercury, but we didn’t have any, and so we relied on telephone communication to know when people were coming, how many, and what the problem was. Did they tell you the details of what had happened? Not really. Not over the phone. But when the people got there, they certainly were providing their impressions. And— What kinds of things were they saying? About being caught by surprise, the cloud coming over some of them, the fact that it sheared and it literally went in two different directions. They did not have clear guidance in where to evacuate to. Part of that was driven by the shearing of the cloud, so when they were told to go in one direction and then the cloud sheared towards that, then other people were telling them, No, you’ve got to go this other way, which was quite roundabout, to get them out. And so that caused confusion, but there was good reason why that occurred during their evacuation. And so they went through, were decontaminated; we were doing the whole body counting, the thyroid counting, just really doing everything we could to remove the external contamination, make sure we had an accurate handle on the internal deposition. And in many cases, they had to take multiple showers. So they would take a shower, come out, and then for the whole body count, didn’t you tell me before there was a— what was that? How was that done? Well, they’d come out of the shower, we’d monitor them. If we could still pick up contamination, then they went back into the shower and they stayed there until they either wrinkled up as a prune, but they had to be completely decontaminated so they would not bring contamination into the rest of the laboratory. UNLV Nevada Test Site Oral History Project 4 How do you do a whole body count, again? At that time, we had what was referred to as a shadow shield whole body counter. The sophisticated one in the large steel room was added quite a bit later. Tell me about what you had. It was essentially like a dolly that a mechanic would use underneath a car, and it would roll from one end, where you could get on it and stretch out and get comfortable. It would then roll through this arch arrangement that had shielding over the detector, and then you’d roll out the other side full- body length, so then could get up and not have to worry about trying to climb around the detector and the shielding. I see. A very simple, simple design, not very, very low background, obviously. We jokingly called it the sky shine machine, on occasion. Sky shine? You’d see background from cosmic rays, things like that, that had the background up. But then much later, we had the very sophisticated whole body counter where the entire thing was pre- World War II steel. Everything that went in was counted to determine if it had a gamma contribution in the metal. And anything that did simply wasn’t used. We’d find another source with a lower background. Yes, that’s what I was remembering, so thank you for clarifying that for me. And that one, we were able to do lung counting for americium, because of the extremely low background inside the chamber. But while the people were going through the process, the other individuals remained on the bus. So we’d take them off one at a time until they were through the shower, and then we’d UNLV Nevada Test Site Oral History Project 5 have one in the shower, one in the whole body counter, one getting the thyroid, and then to a conference room where they were held until everybody was done. And so the guys on the bus [ 00: 10: 00] opened the windows and started having conversations with others that came by. The next thing you know, there were articles being passed to the people on the bus, and as the night wore on, they got more and more inebriated. And so I mentioned the one incident where the person came in so drunk and they took his wallet and his money and other items and they bagged it. Nye County deputy sheriffs were there, actually, and they would bag the items so they could be counted to see if they were contaminated. And they weren’t, so when the people were ready to go to town, they actually received those bags back right then and there. But the one individual came in and he got rather belligerent with the technician that was trying to take the stuff and told him not to steal his money because he knew who had taken the stuff from him. And the technician was irritated by that point and politely informed him that he was so drunk, he wouldn’t remember anything tomorrow, so if he gave him any guff, he was going to keep it. But it was very early in the morning when they were ready to have the bus go into town and actually take these people home. And they’re wearing these paper coveralls and paper booties, and carrying a little plastic bag that has their personal items in it. And the bus literally took each one to their home and dropped them off and made sure they got in all right. But I could just imagine the family members scared to death, having no clue what’s happened to their loved one, and sitting up all night, and the next thing they know, their husband comes in three sheets to the wind in paper clothing, carrying this little plastic bag. So, [ it was] very difficult to explain to the family members what had occurred and how they ended up the way they did. But that was the process that we went through. So I actually was dropped off at my home somewhere between five and six in the morning. Then I had to go back in at noon, and we started working prolonged UNLV Nevada Test Site Oral History Project 6 shifts where we’d be on twelve, off twelve, on, twelve, off twelve. And when they could, then they would cut that back and we went to a three- shift operation. And what were you doing? What was the work that you were doing? We were actually analyzing the samples that the monitors were taking in the forward areas. They had to go through and swipe everything: all of the housing, cafeteria, everything that had been in the fallout path, and routinely swipe those to determine the rate of decay of the radionuclides and then know at what point they could finally let people back into the forward areas to resume work. And that went on literally for months. I think the last folks actually got in and started work roughly four months later. And when you spoke about the families, I just don’t know this, was there publicity or information into Las Vegas immediately, or was there a lag, or did the families have, or your family, if you were still married, have any way of knowing that you were involved in something? In our case, because we were in the lab, we could call and say, Honey, I don’t know when I’m [ 00: 15: 00] going to be home. I’m here, and you know, not really saying a lot but to say, there’s been an incident and we have to work through till we’ve got things down to a dull roar. But I’m positive they released press releases that morning, so people were aware there was an event that had occurred at the test site to some level of detail and that there were people that were being decontaminated. What was the mood like those first days and weeks? Hectic. We knew that we would have a lot of work, but we never dreamt of the thousands and thousands of samples that would come pouring in. They took swipes and air samples of everything. They really wanted to make sure that there were no hot pockets that people could go into, that they really knew and understood the extent and location of the contamination and when UNLV Nevada Test Site Oral History Project 7 it was safe. So, as I said, it was a long day and it was stressful, and then to immediately double back into prolonged long days, very difficult. I can remember walking into take over the graveyard shift after we’d gone into the three- shift basis, and in the sample receiving preparation area, the light was out. And I thought that odd but I turned the light on and there was this pile of towels on the lab counter top. I walked over to walk by and I realized the person I was relieving was sound asleep in the middle of all these towels, because they could get some padding to the stainless steel lab top and stay warm, because again, it was winter. But that was somewhat bizarre. And you just grabbed some rest whenever you could. You just knew you were going to work hard and long. Now do you recall, when you’re doing these samples, are you getting anything unexpected or do you have any way to gauge what you’re expecting? It was typical short half- life fission products. There was nothing unique about it. The same kind of analyses we had always run. And you could sit there and you could plot it. Without even taking the samples after the first few days, you could tell when it was going to decay out to the point where people could go back in. But they were very concerned and wanted the documentation, and so we continued to analyze the samples that came in. Now do you have any sense in your lab what the mood is in Mercury and among test site workers more largely, and specifically about what happened? Are people wondering actually what happened at this point and discussing it or—? What caused it? Yes. Oh, that was a subject of serious debate for years afterwards. I don’t know that you can get five people that were involved in the same room and get the same answer. But it was clearly a UNLV Nevada Test Site Oral History Project 8 situation that they were in a formation they were not familiar with. They had large amounts of water that they had put down hole. As I understand the documentation that came out of it, they essentially, instead of dealing with air, they were dealing with the liquid, so you had different pressures and the stemming simply held it but it found every other crack, including the fault that was nearby, and pumped the stuff out. So you recall specifically at the time what people were speculating about it? Was there awareness there was a fault, things like this, early on? There was an awareness with the scientific community where the faults were on the test site, but they just simply didn’t expect the pressures that occurred to travel the distances they did, because [ 00: 20: 00] they had no prior example to draw on. And so that caused the scientific community to go back and totally reassess the way they did containment, and they instituted the Containment [ Evaluation] Panel that would review all of the plans prior to approving the event, far more sophisticated level of review than what had gone on before. And quite frankly, as a result of that, they never had a real serious leak again. So it worked, but it was a shocking way to find out that things weren’t quite as straightforward as people thought. And as far as the general population, they weren’t working so, you didn’t have that source of feedback when you were out there on the job, the people who would have been in the forward area. You had all of the people that were normally in Mercury there, but they simply were not the population affected. So there wasn’t a lot of speculation or discussion on it. Did testing have a delay because of this? Oh, yes. They had to delay and completely reviewed the incident, and they put in place measures then to head that type of a problem off in the future. And a good example is the Containment Panel. They completely changed the way they did business. UNLV Nevada Test Site Oral History Project 9 Now you were saying before, was it in reference to this, myths or reflections that you might have, or was there anything else in retrospect when you look back now? That was— That was one of the key moments in my career, going through that, and of course, those are the things your long- term memory retains. The day- to- day incidents, they fade quickly. So I can give you details about what happened that day. I can’t tell you a single thing about what happened the day before. In a later job that I had, I found that phenomena to be brought home very, very clearly. When I was a Dosimetry Liaison Officer, I handled all of the requests for exposure information, and that covered from the creation of the test site right on through to the current information for anyone that wanted it. It could be an employer that wanted to know the individual’s exposure history to know if they could use them as a radiation monitor in a power reactor, typical example, where the limits had to be known and they couldn’t be overexposed beyond the guides that were in place; all the way to the grieving widows that wanted to know what the exposure was that caused their husband to pass away twenty years later, who smoked two packs a day, all these other potential causal effects. But invariably, when I was dealing with the widows or individuals that had been out there in the service, they remembered vividly the first time they were involved in an atmospheric shot, exactly where they went, what they did, and they had thought through that information so many times that they would pick various pieces that they felt were the reason why they had developed the various ailments later on. And of course, many of them had absolutely no basis in science, but those were the memories that stood out; therefore, that had to have been the cause of the problem. [ 00: 25: 00] A good example of that is with the Smoky personnel, when Dr. Glyn Caldwell first came out with the fact that there were increased incidents of soldiers with leukemia from the UNLV Nevada Test Site Oral History Project 10 Smoky shot. Because that’s what they remembered. When you went back and looked at the data and actually saw where these people were, I believe there were eight involved and only two or three had been in the forward area. The others had never gone forward for the test. And so the next question is, what do they have in common? Well, they were all in Camp Desert Rock. It wasn’t something that was manifest beyond that— so it couldn’t be that they were allergic to the dye in the uniforms or anything like that— but it was something unique in Camp Desert Rock that caused that statistical increase, or it was just like a lot of statistical data, just a random spike that occurs. But it wasn’t due to the exposure from radiation. Now that’s reminding me, Robert. Is that what that article you wrote was about, that I asked you about? That one was where a widow wanted to know— she was very specific about her husband having been there flying one of the missions in regards to an experiment associated with a nuclear shot. [ She] wanted to know: where her husband was, how far away at the time of the shot— believing that he would be very close and as a result, exposed and no record— therefore the cause of his ailments and the fatality then from that. So I was able to go back and, looking at the historical documentation, know exactly where his aircraft was at the time of detonation and what direction it was heading and the speed, because it was all documented in the experimental records that were generated at the time. And I could respond back to her with assurances that her husband was so many miles away, going in the opposite direction, and that would not have had an exposure from that. Could have had exposures from a dozen other things, but certainly not from that. And this was something that you did as a liaison officer, then, for DOE [ Department of Energy]. Yes. UNLV Nevada Test Site Oral History Project 11 Do that kind of research. Yes. Interesting. I want to go back to something you said at the beginning of this section, to make sure I understand what you’re saying. You said that the day of Baneberry was a key day for you in your career, if I understood what you said exactly. Yes. Key memory. Key memory in your career. Is really what it was. So was there something beyond the fact that it was an unusual and crisis situation that made it key, or was it just that? That was the primary driver. It was a truly memorable day. You knew it was significant. This was not something that was a regular occurrence. It was a once- in- a- lifetime event. And you wanted to make sure you were doing the very best you could, no matter how tired you got. And from day one, I said in previous interviews, we felt we were there to help protect the individual. And so we wanted to make darn sure that we got them decontaminated, we got accurate information on the level of their exposure. The appropriate scientists could then do chelation, if appropriate, for thyroid uptake, things like that. [ 00: 30: 00] So what was your response with the lawsuits, the Baneberry lawsuits and those kinds of things? Were you involved? Where were you at that point in time? I wasn’t involved in the lawsuits, but the individual that was in the next office to me later on when I was the liaison officer was heavily involved. And so I had the benefit of his interpretation of the events and the facts. And I was aware of the preparation he went through, working with the attorneys, the Justice Department. Then later on when I was the liaison officer and I had the UNLV Nevada Test Site Oral History Project 12 responsibility for the communication with various attorneys, others, I had a sense of the potential significance. And there again, I really wanted to make sure we had accurate information that we provided out, and if there was something I could go a little further with in the formation, to help clarify, I did that gladly. But it was very frustrating in the sense that in many cases, it was irrelevant what you provided because it didn’t resolve the grief that they felt. And so in some cases, I got pen pals where one question would lead to two more. In some cases, I knew that there was nothing I could say that would give them comfort and help them move on. And so after a period of a few years, I literally burned out. I needed to get away from that environment. And so when I had an offer to go to the Department of Energy, ERDA [ Energy Research and Development Agency] at that time, I took it. What were your symptoms of burning out? What started— what—? Emotional. Feeling dead. Feeling dead emotionally, physically tired. I always like to have challenges in my work and I like to stretch. And I certainly didn’t want any of that at that point. I just simply wanted to get out of that environment. So when you say “ emotionally dead,” people would tell you stories and it didn’t— I’m trying to imagine what that felt like to you. Usually you’d heard it all in one variation or another before. And so you just simply did not have any kind of a response. No empathy at all. And so I realized I wasn’t doing them the justice they needed. And I certainly was not doing myself any good. And so I grabbed the opportunity when it presented itself and moved on. The person before me had had problems in the job. What kind? UNLV Nevada Test Site Oral History Project 13 I think some of the same. Just feeling overwhelmed with the correspondence, the inability to help the people through so they have closure. I cannot dream of somebody being a psychologist or psychiatrist now. No way. I think I asked you this before, but are those kinds of records, is that public record, or is that correspondence private? No, that’s all covered under the Privacy Act. That makes sense. Along with the actual written responses, the exposure information, the cumulative exposure information on any given individual, all of that’s Privacy Act. Which in some cases is unfortunate because there were some great stories. If I had a fresher, younger point in my time, [ 00: 35: 00] that would be worth culling through if one could get permission and not using the individual identification information. But the psychology aspect, I think, would be an interesting study. I do, too, that��s why I was asking you about it. I think that that’s an interesting human part of that story of trying to make sense of this scientific information as it impacts health and questions and secrecy. It brings in a lot of, I think, important elements of that world. Now I can say that we had occasion where Pat Broudy , who is extremely well known amongst the atomic veterans— her husband had been in the service and passed away— she very politically active, and came up to our facility and spent a day. And Martha DeMarre, who is still over the Nuclear Testing Archive, and myself met her in the morning and offered whatever assistance we could provide, and she and her daughter spent the entire day there retrieving documents, looking at documents, explaining them. And when she finished and was ready to leave, she told us that that was the first time she felt that she had ever been treated well by anyone in the government or UNLV Nevada Test Site Oral History Project 14 associated with the government. And she felt very comfortable in what we had provided to her in the way of explanations and information. So that made us feel good. You know, here’s the classic critic of the inability to get information saying that we had served well. I can’t say that everyone we tried to serve felt that way, but that’s certainly the way she felt that day. Do you have anything else you can think of on that subject? No. Pretty well sums it up, really. OK. I’m going to go ahead and pause, then. [ 00: 38: 00] End Track 4, Disc 1. [ 00: 00: 00] Begin Track 5, Disc 1. When Nancy’s [ Robert’s wife] mother— her dad passed away in southern California— her mother then relocated to southern Utah. Along the way Nancy got several of the books that her father had had, one of which is the Northrop history that had been prepared by Northrop and given to the employees or sold to the employees. And in thumbing through it, I saw a photograph of a hangar and two unusual aircraft and I read the caption. During the winter in the forties, they had extensive rains like we have now. And Edwards [ AFB], Muroc at that time, was flooded out, so they couldn’t flight test there. And so they literally came here to southern Nevada, built this hangar, a very small little storage shed that was probably not even four feet tall, and had these aircraft there in a very unusual place in southern Nevada. But I recognized the lake bed by name because the railroad runs right by there. And my father, having been with the railroad for his entire career, I was very familiar with it, and it wasn’t that far from where I lived as a child. In Desert? In [ California]—? It is near Desert, yes. And so I got very intrigued with that because my folks had never talked about that. And so I analyzed the photo and realized there were some key indicators: a power UNLV Nevada Test Site Oral History Project 15 line, the proximity to the edge of the lake bed, the mountain range in the background. So I pulled old maps, found the power lines, and determined it had to be one of two locations. So the first field trip I went out, it wasn’t there. And the next field trip we went out and drove right up to what was left of the foundation, and got out and there were pieces of aircraft laying around, small pieces, bits and pieces. So there was absolutely no question we had the exact spot. The mountains lined up, the power line, everything. I can reproduce the photo except for the hangar, and have done that. I’ve actually got a PowerPoint slide where I’ve done that. [ Copy provided.] And so then I started trying to find additional information about what went on there. And through a variety of sources, I was able to find that the first all- magnesium aircraft, the— God, I can’t remember. They called it the Bullet. I can’t remember the designation right now [ Northrop XP- 56 Black Bullet]. But the second model of that was flown there and reached the altitude record for the aircraft, which wasn’t that high. The first time they flew that aircraft was there. The second one. They had the N9M miniature wing, Northrop wing, and it’s the one where they changed the various control surfaces. They actually had a total of four built. But they changed the control surfaces and determined the differences in flight characteristics, and then that went into the design of the original full- sized flying wing bomber. One of the N9M aircraft exists today, and they have it at Chino, at the air museum, and I’ve actually seen it flown, but it’s not the one that was there at the facility. Two of them were outright destroyed, and the fourth one, the Smithsonian is reported to have the wing portion but they don’t have the wheels and all the rest of it. [ 00: 05: 00] The other aircraft that was flown was the XP- 324 or 334, depending on which historical reference you read, and it later became the first rocket- powered aircraft the Air Force UNLV Nevada Test Site Oral History Project 16 had. It was in essence a giant hang glider, and at the facility, that’s how they operated it there. They would take it up and then release the tow line and it would glide back. But all three, very unique aircraft. And no one knew that that even occurred here. This is after the war? Yes. Shortly after. Forty- seven. The last time that the glider was known to still exist, it was back at Wright- Patterson [ Air Force Base, Ohio]. There’s a photograph of it with a military officer, Air Force officer, looking at it. And it flat disappeared. The museum has no knowledge of what happened to it. As I say, the four wings, two of them went their way and there’s still the one that’s been restored and is flying. And the Bullet is at the [ Paul E.] Garber facility at the Smithsonian and has not been reassembled, but it’s there, all of the pieces are there, and it’s available for restoration. But they actually had to develop the technique of heli- arc welding in order to weld magnesium, which is highly flammable.