Fumigant Application

John B. Mueller [00:00:01]:
This podcast supports fumigators in improving safety, compliance, and solutions. Always follow the federal fumigant label, state, and local laws. Licensed fumigators are legally responsible for their applications. And now, on to all things fumigation. Out here, we don’t just fight pests, we outsmart them. This is All Things Fumigation, where applied science meets real-world grit. I’m John B. Mueller, a fumigator by trade and your guide to the science of fumigation done right. Each month we saddle up with the people, the practices, and the precision it takes to keep facilities safe, compliant, and pest-free. Because when you’re in the trenches of pest control, You don’t need magic, you need science and maybe a little cowboy spirit. Smarter solutions, safer practices, managed costs. Welcome to All Things Fumigation. Welcome to the next episode of All Things Fumigation. Our sponsor for episode 8 is Spectros Instruments, and I’ve worked with Spectros for about 20 years, and they develop and distribute clearance devices for fumigants, and then high-range efficacy monitoring. And I’ve had good relationship with that group and very beneficial. We’ll show some examples of how we’ve utilized that technology in this episode a little bit. One thing I can’t go without saying, anybody that knows me knows I’m a big Indiana Hoosiers fan, and I wanted to shout out to the national champions, Indiana Hoosiers, for their victory last Monday. Very, very exciting game. After the game, I heard Coach Cignetti interviewed, and one of the things that he had mentioned, they asked him about comparisons that were being made between Bob Knight and Coach Cignetti, and he humbly rebuffed that. But one of the things that he did say is he respected Coach Knight and one in particular, one of the things that he said, and it was really centered around championships. And when they asked Coach Knight, you know, what it takes to get to that level, he said, you know, everybody wants to be a champion, but not everybody wants to do the work to become a champion. And I think that’s kind of a universal truth. And I’m going to relate it in kind of a flaky way to fumigations. Fumigations are extremely difficult. Everybody wants to be successful doing this work, but it requires putting in the effort to be successful, and that’s probably going to be not highlighted any better than in this episode, which really is focused on fumigant application. One of the other things I wanted to do as housekeeping is let everybody know, if you haven’t heard, The Fumigation Company is hosting a post-harvest fumigation school. The theme is Applying the Science of Fumigation. It’s June 9th and 10th of this year, and it’ll be held at the International Grains Program Institute on the campus of Kansas State University. So we’re excited about that as well. So If you want more information on that, you can go to thefumeco.com, and we’ve got a page under About for anyone that wants to sign up and register for that, that training. Our viewer question this episode is from someone I’ve known for quite a while, Nolan Bernard, and he was watching the last episode and made a comment really more than anything and I thought it was really good to bring up from a safety standpoint. You know, his statement was, you know, you must seal all potential leak points, but we come across sealing situations where you just cannot access them. What is your advice? These are usually safety issues. And it really comes down to a mindset. You know, many times when we go and visit a facility from a from a fumigation perspective, it depends on what lens you’re looking at that site. You know, are you looking at it to sell or to, you know, prepare budgets for that? Or are you looking at it from an operational perspective? And you really have to do both. And that’s where you pick up some of these nuances and some of these challenges. And And really overcoming some of these difficult sealing scenarios comes in the planning and preparation of the fumigation. I’ve had people say there’s no way to seal a certain, you know, feature, and it’s just not possible. But in the planning stage, anything’s possible. I can tell you that we’ve had situations where we’ve brought cranes in to address really difficult sealing challenges. We’ve even hired window washing companies and industrial bridge cleaners and painters to come in to rappel, to seal certain areas using their safety standards. So it can be done. It does require advanced planning. And it really comes down to if you’re at a point where you weren’t able to do that, you did find a seal that’s up high and it could compromise the fumigation, you really have to fall back on is it really suitable to treat then or should that be delayed? Safety can’t be compromised. So that’s really not an option. But focus on the planning side of that. We’re going to get into this episode now. Like I said, episode 8, it’s gas application. And as you know, we’ve, we’ve put together themes for each one of these segments. And this theme is releasing the hounds. And people that have worked with me understand that When we’re all suited up and we’ve got SCBAs on, we’re mic’d up with our radios. Many times we have different groups releasing fumigant on some of these bigger jobs. And the callout when everything is safe and everything is locked and everything is clear and it’s time to release gas, the callout across the radio is “Release the hounds.” And that means it’s time to turn the valves on. You know, open the flasks and start applying the fumigant. So that’s what I’ve chosen for this episode. We’ve gone through this fumigation process, we’ve gone through the planning phase, we’ve talked about preparation and setup and sealing. Now we’re in application, gas application, and this is a pretty dynamic step in, in this overall process.. We’re going to really focus more on the nuances that impact and require special consideration from a gas application standpoint. And the goal that from my perspective that I always set for this is, you know, we’re going to apply fumigant and maintain efficacious dose to the pest you’re targeting.. And that may you seem, know, relatively intuitive, but what’s not intuitive is some of the legacy labels that we’re going to point out. You’re going to hear me say over and over again, there’s a difference between, you know, the tactical behavior of fumigants and really more of the prescriptive or precision nature of how we fumigate. And I chose 3 insects on this screen that really kind of highlight that, right? Not all insects are built the same. Some are more difficult to kill than others. We know Indian meal moth, which is featured on the left if you’re viewing this podcast, is relatively easy to kill for many different reasons. Cockroaches are also relatively easy to kill. They respire very quickly. Red flower beetle is one of the most difficult to kill because of the, the nature of the egg and how difficult it is to penetrate that egg. So not all insects are built the same. There’s only a couple of dozen store product pests that we’re going after, but they have a very wide range of susceptibility. So If you think about the stages and what we need to know to be successful fumigating from an application standpoint, you know we cannot fumigate with a dose concentration alone. We can’t go through a fumigant label and select a dosage rate based on our conditions, apply that rate, and walk away, right? We have to understand the dose concentration relationship. So once we understand how that dose that’s specific to your fumigation, how that relates to a concentration, now we know whether once, once the gas is introduced, we know if that is, is the proper dosage rate that we’re looking at from a gas monitoring standpoint. If we don’t understand that, if we’re not observing that, We don’t know if we’ve put too much in or not enough. We don’t know where we’re at at that point in the treatment. And then the next thing we need to know is an endpoint, right? We need to know what that target or that treatment endpoint is. And that can be expressed as Ct that we’ve talked about, concentration and time, or it could be ppmV, so parts per million over time. And I really look at this as I think of it this way. I, you know, a fumigation is a journey, right? It’s we’re going on a hike. You’ve got to know where that trailhead is. You’ve got to know where to start and you’ve got to have an endpoint in mind. And then once we have those two points of correlation, we can then follow that path to success. And we’re going to show some examples of that. But in terms of generating that starting point and that endpoint, we really need to understand how these, these labels, these, these federal laws that we have to follow help us with that journey, with that fumigation journey. And so I’m going to kind of compare and contrast legacy labels, and it’s kind of like a yin and yang of, of what we’re trying to accomplish here. These legacy labels are very tactical. We’ve mentioned this before in earlier podcasts. So some of the older fumigants that have been around a while— methyl bromide, metal phosphides, and then even the cylinderized phosphine products— got roped into these old structures, these old tactical structures. But then we’re going to look at how the modern labels are today that are much more prescriptive. Sulfurofluoride is extremely prescriptive. USDA on their import side are very prescriptive in, in some of their treatments. And then I believe future labels you will see will be much more situational, much more prescriptive. If we take a look, if someone is having a hard time understanding where I’m coming from with these comments, just take a look at the USDA treatment manual. What that treatment manual does is it really recognizes that not all insects are built the same, which is what that tactical label suggests. And we’ll peel that onion apart a little bit more, but it takes that tactical label and makes it very prescriptive. It takes an invasive pest, a quarantine pest, it takes the science behind that pest in terms of controlling it at a very high level, and it really supersedes or dictates the treatment beyond the legacy label. And if anyone is looking at me or thinking a little cross-eyed right now about that, just take a— just consider capra beetle. The capra beetle treatment manual shows concentration dosing well beyond what the methyl bromide label allows from a domestic treatment. And, and then it has standards along that. It has a CT that builds to and, and requires certain levels over time that are very high concentrations. So, you know, USDA in their own treatment manual have taken that tactical legacy label and made it very prescriptive. So let’s take a look at dose-measurement relationship. So we have a dosage rate, we know what that is. Let’s use methyl bromide as an example. We’re dosing at pounds per 1,000 cubic feet. Well, how does that relate to concentration? I think many times we just take for granted that We dose that amount, we jump on the high-range monitoring device, and whatever that number is, whatever that value is, is, is where we start that process. And, you know, that, that can serve us. But we know that there are 16 ounces in a pound. And as we change phase of matter from the liquid methyl bromide that we’re administering and changing that to a gas phase of matter, we know there are then 16 ounces of methyl bromide suspended in the air per 1,000 cubic feet. So that’s our start point, right? That’s, that’s where the trailhead is on this fumigation. So it’s really important to understand that if you don’t now. Now we, we change things a little bit when we consider the phosphine concentration dosing, right? So we’re dosing in grams. And as an example, one tablet of metal phosphide, of aluminum phosphide, it weighs 3 grams, but it off-gasses 1 gram. So based on our concentration, we know how many tablets we’re using. If we’re using pellets, it’s a fifth of that. You divide by 5. To come up with that. But we know our gram dosage rate, so we know what our concentration should be suspended in the air, and then we can take that journey from there. Cylinderized phosphine, same thing, but we’re in liquid grams, but the conversion is the same. Now with sulfur fluoride, we go back to ounces again, right? So, you know, 1 pound of, of liquid sulfur fluoride per 1,000 cubic feet is 16 ounces suspended in the air. Easy, right? All this is relatively easy, but we have to understand that transition between dose weight and measurement to really start that journey and get off on the right foot. Now, one thing I want to point out is when we’re choosing our dosage rate, where does this come from? You know, I mentioned, you know, legacy tactical labels, and this is a great example of that. When we look at— this happens to be— this is the dosing page for a metal phosphide label. We go through the selection process for our fumigation. And in this scenario and these legacy scenarios, We’re looking at pest not as a dosing strategy or a treatment strategy, but more as a warranty and claim. We’re not tying the pest to our dosing selection. Commodities is pretty true, universally true. We have to make sure that the commodity is listed as well from a residue standpoint. But on the metalphosphide label, it’s really type of fumigation where our dosage range selection comes from. And it— there was some intuition built into this at one point, but when you think about it objectively, it doesn’t make a lot of sense, right? There’s all these different scenarios and types of structure structures, and they’re assuming that certain types of structures are looser than others. And for the most part, that’s accurate, but it’s not completely accurate. It’s not always the same. Um, so it’s really more around volume and the tightness of that structure, and then how that fumigant impacts that specific pest. I would even go as far as to say these legacy labels really need to be changed and tied to more of the scientific behaviors and requirements to effectively control these insects. But there’s also a nuance to phosphine that’s a little different that we’ll show you as well. So let’s explain this a little further in terms of tactical and prescriptive label and guidance. If we break these labels down into structure, pest, temperature, and half-loss to determine dosage rates, the tactical labels list structures. The prescriptive label It, it, doesn’t. it’s— they understand that’s neither here nor there. It’s more about the volume and the tightness of that structure. Pests are listed, but pests on the tactical label are more, as we mentioned, a warranty claim, whereas a prescriptive treatment, it’s tying to the dosage schedule to target that pest. Temperature is listed, you know, on both, yes, but on the tactical label, it’s more around assuring that you’re above a boiling point. Like with methyl bromide, the boiling point’s 38.5°F, so you can’t go below that, or it doesn’t— or the methyl bromide doesn’t change phase of matter from liquid to gas. So you have to be above that 40-degree level. So, and then with phosphine, with the metal phosphides in particular, it’s, it’s also a function of the rate that, that the solid changes to a gas. It slows it significantly. So prescriptive treatments, it looks at temperature for sure because that influences the behavior of the insect, and that’s its primary focal point. And then the last one is half-life time, and this is where the art of fumigation comes in, is is an experienced fumigator can look at a facility and based on the construction material and the dynamics of that, after reviewing that structure, they can— if they’ve never treated it before and if there’s no data on that facility, they can come up with a pretty good estimate of what that half-life time is. If the fumigation has been performed before and you have performance data, monitoring data on that fumigation, You can then just input the half-loss time that was observed on those prior treatments. But the tactical labels don’t require a half-loss time assessment, and that’s where they really fall off. So if you don’t have 2 points of correlation, you can’t come out with that endpoint. If you don’t have a half-loss— if you don’t have an endpoint standpoint, you can’t have a half loss. You don’t know if that path that you’re following is getting, getting you to the solution that you or your customer are looking for. So we’re going to take a look at that from a fumigation journey standpoint with a methyl bromide fumigation. In this situation, we’re looking at a graph that starts out with a pound and a half dosage rate. So our trailhead, our beginning of this journey is at 24 ounces. We’re looking at a CT of 320 ounces, so C over T. And if we’re estimating a 12-hour half loss time, we want to see 12 ounces at 12 hours. If we are not trending to achieve, if we’re hitting 12 ounces prior to 12 hours, We know we need to bump up. It’s just that easy. We don’t need necessarily a dynamic, you know, computer program to determine that. But if you have one gas reading that you’re taking, that’s the case. But when you’re doing 4, 8, 12, 16, you know, 24 gas readings on a job, You either have a program that’ll help you assist with this, or you’re on a calculator constantly for 24 hours. So this is a good example of the basic process. And but then things scramble a little bit when we move away from methyl bromide and we focus on phosphine. So what we understand very quickly is this is a much slower fumigant reaction, right? Metal phosphides react slowly over, you know, 18 to 30 hours depending on temperature. So we won’t see peak concentration generally on average until about that 20 to 24 hour range. Now what’s happening in that period of time is we’re losing gas, there’s some competing surfaces that can challenge gases and bring that concentration down. So even though a 60-gram dosage rate— and remember, you know, 1 gram suspended in 1,000 cubic feet is 25 ppm. So we simply take 60 grams times 25, that gives us 1,500 ppm. Well, you’re not going to see that theoretic maximum because you’re going to be leaking likely to some degree within that, you know, 18 to 30 hour period before you hit your peak concentration. So you’re doing good. You’ve got a relatively tight structure if you’re seeing 80% of that theoretic maximum. So you don’t panic if you see less than, than that max theoretic maximum. But you also know when the gas starts to to really slow down. After you hit that peak, you see that drop in your linear line for monitoring. And look, these— let’s be blunt— these are very subjective concentrations, but they’re educational and representative of what we’re seeing in the field over time. And one of the things I wanted to point out that we’re learning about phosphine is We don’t have a CT for specific insects, so essentially we have to say we have to look at worst-case scenario. And if we’re going to look at all stored product pests, we need to draw a line not to, you know, not to, not to fall from. And what we’re seeing from, from research out there from Dr. Spencer Walsh from some Greek research that’s come out recently, that hard deck for phosphine is 500 ppm. And if we’re looking at a 72-hour fumigation, one thing I want you to, to understand is we’re not hitting 500 ppm for several hours. And then on the backside of these fumigations, we’re falling below that 500 ppm level at prior to the end of the treatment. So if we’re needing to drive these concentrations, our treatment strategy has to recognize this. In this scenario, we’re spending half of our time, 31 hours, below that 500 ppm hard deck. And when we’re looking at fumigation failure or perceived failure, It’s not the fumigant failing. Again, we’re going to repeat this. It’s our strategy that’s failing. The journey that we set up didn’t get us to our endpoint because we were, we were focusing on the wrong endpoint in these situations. So the other challenge with this is, you know, again, we— what is the— how do you figure in half lost time? On a metalphosphide treatment that’s evolving over, you know, a day or day and a half. That makes it very difficult. You’ve got a moving target. And then the other thing is, you know, how do you stay above 500 ppm with metalphosphides? It’s, it’s very difficult to do that as well. How do you redose with a solid fumigant? In most instances, you can’t. So if we change gears yet again and look at cylinderized phosphine, it’s again, we don’t have that big camelback hump in the treatment graph or in the linear process. We are putting that gas out very quickly, but we’re also dropping below that 500 ppm line in many instances relatively quickly. Quickly as well. And redosing is a reality of some of these treatments. So keep that in mind. We can get back to looking at half-life times. We can start treating this, you know, just like we do the rest of the cylinderized phosphine products. And we have to be ready to monitor closely and redose accordingly and keep above that 500 ppm hard deck. Then if we take a look again at sulfonyl fluoride, you know, we go back to more of the methyl bromide strategy of where that trailhead is, what that dosage— initial dosage rate is, how that relates to concentration, where that half-life time is, and then where that endpoint is, where that CT is. What are we targeting? And this is where the FumaGuide, which if you’re not familiar with it, it’s a computerized label that we input all the dynamics of the fumigation and it sets this path for us. It gives us a map of what that treatment should look like from, again, what the initial dosage rate should be, what the end CT should be, and then it is monitoring every step of the way. If you input gas concentration during that journey, it will tell you whether you’re on track or not. And it’s a fantastic tool to help drive results. If people aren’t seeing the results that they want with sulfur fluoride, you know, with the fumigator using this tool, they’re either not monitoring or they’re not paying attention to the outputs from the Fumiguide. It will take you where you’re— where you need to be as long as you’re inputting the right information. You’re putting the right temperature in, you’re putting the right target pest in, it will solve the problem. And it would be really nice to have a tool like this for the other fumigants. All right, I want to take this opportunity again to thank our sponsor Spectros Instruments. For this episode, Episode 8 of All Things Fumigation. I’d also like to take this chance to ask you to please like us on your streaming source. Give us a like, means a lot to us in the effort and work that we’re trying to do with this market. And then also, I want to remind you to give us your feedback on this episode. We need your suggestions. We want to use these questions, comments, and concerns on future programming. Even if I’ve said something that you disagree with, throw it out there. This is how we learn, and we’ll go back and address that and clean that up if needed. But we really do appreciate the impact, the input. I love hearing it. I love the discussions that come from that. Now, getting back on track for gas application. There are a lot of considerations in terms of what we’re targeting, in terms of what type of fumigation we’re targeting from a gas application perspective. And the 3 primary groups in this post-harvest spectrum is bulk commodities, bagged commodities, meaning like in warehouses, sometimes transportation, and then also food processing environments like flour milling operations bakeries and things like that. And they’re very different in the treatment approach. We’re not going to get bogged down on the minutia that’s required from an application standpoint for each one of these. But we will focus on these, we’ll break these out in future episodes. I do want to touch though, that being said, just briefly on these these, these 3 different avenues, so to speak. And when we’re approaching, you know, say commodity fumigations, those structures can vary greatly. The majority of what we’re looking at though are vertical storages. So the question is, where do we dose? Where do we measure? And if we have to add gas and if we can add gas, where do we add gas? And, and really, We’ll go back to how do these structures hold gas? How do they leak? What are the mechanisms? We know there’s convection going on in these, these storages of densely packed material. And to get gas loss, you have to have fresh air introduction. And in a vertical storage, we do see that. We’ve talked about this before on the podcast. So our leakiest points are around the bottom and at the top. But unfortunately, these are our only opportunities to add gas. Generally, I will say that the head section of these storages is traditionally the most leaky. So keep that in mind when you’re dosing. Now, The bottom can be leaky too, but when you’re introducing the gas, you can throttle that, that, that gas introduction many times. Not so much with metal phosphides, but with the other fumigants you can. You can also go around and leak detect and you have to be safe. You have to wear the right PPE when you’re doing that. But what I would do many times is I would take colored hairspray and a low-range monitoring device or a leak detector and find those leak points, spray those where I’m seeing fumigant being pushed out, and then shore that up. You can always shut the fumigant off, make some corrections if you’re seeing too much gas loss down low, seal, and restart. That’s a good way to go with many fumigations. If we’re talking about warehouses, You know, the same, same is true. Where do you dose? Where do you monitor? You know, where do you add gas? And if you look, if you think about a large warehouse full of bagged material, think about where is that gas going to leak, right? It’s going to be outer wall. It’s going to be the roof. So many times your gas application needs to be positioned more in the interior of those structures. You’ll see— we know the gas expansion exists with these fumigants. When we’re doing fumigations like this, many times we’re using the cylinderized fumigant. So gas expansion is very rapid. And what we want to really do is we want to displace air from within that structure. We don’t want it to be fumigant-air mixture. Again, we’re pressurizing this this structure and we’re pressurizing it more than you realize, I believe. And so our strategy wants to be, you know, take it inside a little bit more, release that gas so that we’re displacing fresh air from within that structure and replacing it with fumigant. And looking at processing structures, There’s also some, some bad habits that have occurred that I want to discuss as well. And you can really start to see these from a graphic readout of a guesstimated fumigation. And again, I know we’ve got some listeners and some people viewing the podcast. I want to encourage you to go back and view this one in particular because we do have some visual aids here that kind of help in the process. But what I see in a lot of fumigations is if we’re having to go and add gas quite a bit and it’s not weather-related and it’s not seal-related necessarily, your seals are tight, you’re not having weather, you know, challenges. Many times that’s because we have estimated the half loss too low and we’re having to recover that fumigation. So really paying attention to being more accurate with that half loss. If it’s a first-time fumigation, there’s not much you can do if you don’t have data on that. But if you do have data, you can look at that data and, and to adjust that half loss assessment and be much more accurate with it. We’ve mentioned this earlier, but that’s critical because if you do estimate too low, you’re going to be adding gas frequently. Also, if you’ve got a real disparity in your gas concentrations throughout these multi-levels or these different sections of processing environments— many food processing facilities are very sectioned. If they’re not multiple levels, you know, you’ve got receiving areas that are walled off from processing areas that are walled off from packaging areas that are walled off from warehousing areas. And if you’re not measuring each of these areas and dosing each area according to their volume, you can end up with a significant imbalance. I’ve seen many instances where people just calculate the total, they take their total fumigant needed, and they just start arbitrarily putting it in different areas. And unfortunately, what happens a lot of times is some areas end up with deficient levels and some end up with too much.. And if they are subsectioned, they may not get those deficient areas back up to concentration, not equal to the other areas. So you get this separation, and you can’t put fumigant back in the bottle when you have too much in certain areas. And the only way to recover the deficient areas is to add gas. So that’s avoided by being very accurate with your dosing schedule and you’re treating each of those areas very separately. So one other area is situational analysis when we’re looking at these gas applications. We hopefully are able to have some influence over the fumigation and the timing of that fumigation. Timeline that we build. And we’ll explain some of the impacts that this will bring to the fumigations. If you look at gas concentrations and you’ve read this data very much, you’ll see that wind direction can play a catastrophic— can have a catastrophic impact to these fumigations. What I’ve got on the screen is kind of a tale of you know, two, two conditions here really is we’ve got really heavy gas loss in the first 12 hours of a fumigation, and then it totally stabilizes and flatlines in the back half of the fumigation in the second 12 hours. And, you know, why would that ever be? I mean, it’s dramatic. And in this situation, when we went back and reviewed this, this treatment, we had wind directions coming out of the south hitting a warehouse that was metal construction and had a slight opening in the eave. And it pounded this fumigation for the first 12 hours, had a significant gas loss, had significant gas reintroduction. Then winds— front came through, winds changed, completely changed directions and came out of the north. Out of the north, it was hitting slipform concrete processing construction with very little leakage. And there was no pressurization of that structure, no, no fresh air being forced in. And it held its own and just flatlined nearly for that second 12 hours. And this is the kind of review and preparation for these fumigations that we need to look at., and we need to prepare for when we think about how we’re going to dose these structures. And temperature disparity is another one. When you, when you fumigate and when you seal these structures, if you pay attention to internal temperatures, they do increase when you seal that structure up. Sometimes slightly, sometimes noticeably. Usually if you have, especially in food processing or milling environments, if we’re sealing while cleaning’s going on, there’ll be a lot of complaints about how the mill’s heating up. That’s a good thing, right, for the insects and for the performance of the fumigant. But sometimes it can cause pressures to the fumigation. When you see a 30-degree difference between the internal and the external environments, you really start to put pressure on these, these fumigations. When cold air intrudes, when fresh air intrudes and it’s cold, it drops like, like marbles in that structure and it pushes up, right? That’s where we get the chimney effect and it’s forcing that gas out. So you really have to prepare for that from a dosing strategy standpoint. Point. If you’re seeing very high temperature disparity, you may want to adjust your dosing scheme to be a little heavier on the bottom of vertical structures. And, and kind of go against what I said just a little, little while ago about dosing specific to the area. I’m not talking about dramatic differences. But we know where that, that, that fumigant’s going if we’ve got multiple levels. It’s gonna go up. So plan for that accordingly. It’s one, one possible strategy option for you. And also look at what I pulled up. I use Weather Underground a lot for looking at fumigations and preparing for fumigations ahead, and then also historic data, historic weather performance during the fumigation. They have a segment that you can look at historic data. And what I did here is I selected October 19th of last year, just grabbed it randomly, literally. And what we look at with this linear data is we see 56 degrees as a low nighttime, nighttime low, and we see 80 degrees as nighttime high. There’s a 30-degree temperature disparity. But what is the internal temperature, right? So if the internal temperature— and what we’re always trying to push for in some of these food processing environments is the warmer the better, right? It’d be ideal if it was, you know, 82 or above, especially when we’re using sulfuric fluoride. And if the outside temperature at night is 56 degrees, there is a lot of pressure going on there. We have to account for that. The other thing is, when do we dose? When do we release gas? When do we release the hounds? Right. And we know that during the day we tend to see higher surface winds, higher gusting. And that’s because the solar loads hitting the surface of the earth, heating it up, causing, you know, some, some wind reaction. And generally, once that sun sets, depending on the time of the year, right, You know, in this instance, about 8 o’clock, 8 PM, winds start to die down, and now we get low winds, low gusts for the next 12 to 18 hours, really. So if we get to time it, that’s the ideal time for, for our introduction of fumigant. Now, from a gas application standpoint, we’re going to look at some situational analysis here. We talked a little bit about, you know, gas pressurization earlier and how that could influence these fumigations. And then we’re going to talk about, you know, how different fumigants impact or influence, you know, what we are fumigating. So if we look at a table here and I’ll describe that for listeners too, there are— there’s really differences between what kind of pressure the different fumigant options create for us. Metal phosphides, as you can imagine, very low pressure. There is some, some increase in pressure as hydrolysis occurs, that, that exchange where water reacts with the metal phosphide to liberate phosphine gas. There’s a slight pressure increase, but it’s very slight. It’s over a very long period of time.. But when we get into the cylinderized— excuse me, the cylinderized fumigants, it’s— we’re putting gas in very rapidly and sometimes we’re putting some pretty high concentrations in there. So that conversion from liquid to gas is expansive. And depending on dosage rate and depending on the amount of number of cylinders we’re putting in there is kind of the way I think about it is each one of those those cylinders represents a volume that we’re kind of injecting in there. And what you have to realize is we’re not going to pressurize these buildings. They’re not designed for that. They’re going to seek an equilibrium ambient with the outside, you know, barometric pressure. So that’s going to happen. So either gas is going to be lost or fresh air is going to be displaced, right? We mentioned that. But what does that look like? You know, in the case of methyl bromide, you know, on a 1 200-pound cylinder, methyl bromide is going to, is going to provide 800 cubic feet of volume. Not a big deal because we’re using relatively low doses there by comparison. But cylinderized phosphine, we’re putting in about 550 cubic feet with every Ecofume cylinder as an example. Which is the only blended phosphine product out there today. And again, that can vary based on the temperature, but generally the temperatures we’re working at, we’re going to see 500 to 500 cubic feet of expansion. So now we’re pushing, we’re putting a stress inside that building. So we don’t want to apply where we’re going to have, you know, immediate leak. We don’t want to see high concentrations of gas leaking out ever from a safety standpoint, from an efficacy standpoint. So that’s part of the dosing consideration with, with cylinderized phosphine. We’re using, you know, mass air blenders to take that, that pure phosphine that would normally be flammable, run it through a mass air blender and push that, that nonflammable gas mixture in these structures.. And we’re, we’re doing that at a rate of anywhere from 150 to 250 CFM. And so over time, that is a lot of volume. That’s the highest amount of pressure we’re putting on these structures. So how are we managing that gas introduction so that we’re not losing gas over that period of time of application? And then sulfur fluoride, you know, same thing again. Depending on temperature, around 500 cubic feet per cylinder. So, you know, the pressure we’re considering on those are high. So pressure management is one of those things that, you know, it can kill a fumigation if we’re not careful. I’ll give you an example if you think that’s a dramatic statement. Corrugated metal bin with an unsealed base metal to concrete base of that bin or not, you know, pretty poor construction aeration fan. We’re injecting fumigant in those, those lower portions of the, of that storage. It’s, it’s, it’s expanding very rapidly, the fumigant, and that pressure is going to follow the path of least resistance. And if it can get out down low, it’s going to be leaving in high concentration. There’s a perfect example. Now gas is going out and not up where the insects are. So, you know, kind of a great visual understanding of a scenario that absolutely can kill a fumigation. So pressure management, it either manages us or we manage it. That’s— I’ve said it over and over again, and it’s very, very important. We need to be able to manipulate this gas in with minimal gas loss. And then, you know, the last thing I’d like to end on is, you know, before you release the hounds, let’s go back again. Let’s stop thinking about application tactics. Let’s ground ourselves in safety. Let’s make sure everybody’s clear from that facility. Let’s make sure signs are on, the warning placards are in place anywhere a person can access, and that locks are on and secondary locks are on and in place, and the facility is secure, empty. And then gather your team together and get organized before application. Many times when it’s time to release the hounds, It’s sometimes our backs are against the wall. Our timeline might be drawn out. We feel like we need to be in a hurry. That’s the time when we slow down, we refocus, we listen to the team, we make sure everybody’s comfortable, and then we make the call to release the hounds. So this is the most dangerous part of any fumigation is right at the point of application.. I want to remind everybody to be a science cowboy, apply the science, and protect your product. My last chance to thank our sponsor Spectros Instruments for supporting the podcast today. I want to remind you to like us on your screening— streaming system, excuse me, and that’s important to us. Us and give us your feedback. Again, we’ll use it and create good conversation and learning points. My last chance to plug the Post-Harvest Fumigation School at Kansas State University, June 9th and 10th of this year, and we’re really going to drive kind of a take-home program for you that will be centered around Train the Trainer. This podcast supports fumigators in improving safety, compliance, and solutions. Always follow the federal fumigant label, state and local laws. Licensed fumigators are legally responsible for their applications. I am John B. Mueller, a fumigator by trade,— and your guide to the science of fumigation done right.