EPA vs. Sodium Bromide: The Real Story Part 1 of 2

The EPA’s sodium bromide relabeling decision didn’t just tweak a bottle panel, it pulled a familiar algae treatment tool out of the outdoor pool conversation overnight. We’re joined by Scott Hamilton, the CEO of United Chemical to explain what the EPA’s interim decision actually says, why “not for use in outdoor pools” now shows up on sodium bromide-based algaecides, and how that single change ripples through distribution when big suppliers decide they won’t stock the category at all. 

From there, we get practical and technical. Scott walks us through worst-case outdoor testing designed to stress the chemistry: high pH, zero cyanuric acid (CYA), and heavy liquid chlorine dosing in above-ground pools. We talk bromate formation, why the EPA leans on conservative assumptions like 100% conversion, and what the real-world data shows instead, including the striking difference between treating a pool with active algae versus clean water. If you’ve ever wondered why timing matters, we dig into the “first hour” window where most bromate formation tends to occur and what actually drives the reaction. 

We also zoom out to risk, regulation, and perception: how Prop 65 style warning logic shapes the conversation, how the EPA swim model estimates ingestion exposure over a lifetime, and the question every pool pro asks, why hot tubs still get a pass while outdoor pools don’t. Subscribe for part two, share this with a pool pro who’s navigating algae season, and leave a review with your take on the ruling.

We sit down with Scott Hamilton from United Chemical to unpack the EPA’s interim decision that forces sodium bromide products to remove outdoor pool use from their labels and triggers major supply chain fallout. We dig into bromate formation, what worst-case testing actually shows, and why the first hour after dosing becomes the key battleground in the chemistry debate.  
• who the interim decision affects and why labels now read not for outdoor pools  
• why Pool Corp and others stop carrying sodium bromide products  
• how the EPA reaches decisions when it does not run its own controlled lab tests  
• worst-case outdoor testing design using high pH, zero CYA, and heavy liquid chlorine  
• what the data shows with algae present versus clean water  
• why most bromate formation happens in the first hour  
• how proprietary ingredients can suppress bromate formation  
• how Prop 65 and linear risk models shape public perception  
• why hot tubs get treated differently under the EPA exposure assumptions  
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Download the full Sodium Bromide Study:

https://drive.google.com/file/d/1X6-1uJJ7MZugeRDpch0tpop2vg0hjPR0/view?usp=sharing

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Transcript

Welcome And Guest Setup

SPEAKER_01 0:14

Hey, welcome to the Bulgaria Podcast Show. In this episode, I'll be joined by Scott Hamilton of United Chemical. We're going to talk about the EPA and the sodium bromine relabeling of the products. And he'll get into this in more detail on the podcast. And this is a two-part series where the conversation is broken up into two episodes, so definitely want to listen to the first part and the second part to get the full picture here of the EPA and the sodium bromine. Are you a pool service pro looking to take your business to the next level? Join the pool guy coaching program. Get expert advice, business tips, exclusive content, and get direct support from me. I'm a 35-year veteran in the industry. Whether you're starting out or scaling up, I've got the tools to help you succeed. Learn more at Swimmypoollearning.com. So I'm joined today by Scott Hamilton of United Chemical. How are you doing, Scott?

SPEAKER_00 1:08

I'm doing okay. How are you doing?

SPEAKER_01 1:10

Good. I'm doing good. And I always want to call it United Chemicals. So you have more than one chemical, right?

SPEAKER_00 1:15

We do, but technically the name is United Chemical.

SPEAKER_01 1:21

That's okay. And then if if people aren't familiar with your products, it's the yellow treat and the no more problem. And these contain sodium bromide. And today we're going to talk about this a little bit because the EPA, the EPA has kind of shot down sodium bromide, I guess they can say it like that.

SPEAKER_00 1:40

Yeah, they the EPA released uh an interim decision, which means kind of like a temporary decision until more data comes forward, which is kind of what we're going to be talking about today. And the decision was to remove uh outdoor pool use from the labeling of products. So now if you use uh a sodium bromide-based algecide, you'll say on the back panel, not for use in outdoor pools. So that was the EPA's interim decision, and that's now on our products and any other sodium bromide-based algees.

SPEAKER_01 2:18

Okay, and this effectively made the suppliers not carry the product anymore, right? Is that pretty much correct?

SPEAKER_00 2:25

Some some of them. So previously, most of your listeners probably found us either through Pool Corp and their subsidiaries or Leslie's. Leslie's was also carrying our stuff. Once the

What The EPA Changed

SPEAKER_00 2:40

decision came out and it was then sent to all the manufacturers, we were one of the last to have to change our labeling. But Pool Corp said that they weren't going to carry sodium bromide-based products anymore. And I think Leslie's as well, though I don't know if they gave us any kind of official statement, but they no longer carry uh sodium bromide-based algae sides.

SPEAKER_01 3:04

Now, this of course is a mainstay in the older old-timer pool guys, and even the new guys up to up to the the decision by the EPA, it was one of those things where it was pretty bulletproof to use to treat algae in pools. I mean, they I used to carry a 25-pound bucket in my truck in the old days and just reload my two-pound container. And it's just one of those things where this product is was used so widely in industry. And now we're left with a kind of a hole in the algae battle, I think, in in terms of products. It's so you have a summary, you sent out to all of your followers the actual report that you created on the on the sodium bromide and the EPA. And we can just start with some of the summary points that you have here. And I have some more questions from the report itself. So let's just start with the first bullet point that you had in the summary, which is that the rigorous worst case testing, and we intentionally pushed our chemistry to the limit using zero CYA, high pH, and heavy liquid fluorine to stimulate the hard hardest outdoor conditions. So why don't you go over that one real quick?

SPEAKER_00 4:15

Yeah, so just to kind of explain what the EPA interim decision was about, we actually talked about this some time ago, about the the EPA's, I think, different studies from like 2005, or at least their internal discussions about potential bromate formation. And so the EPA that was back in 2005, they've since revisited what they were looking at, and they asked the manufacturers to provide data. So they wanted data on bromate formation. There was a group of manufacturers, particularly Lonza and ICL, which is kind of a which is a raw chemical manufacturer in Envirotech, formed what's called the bromate workgroup, and they supplied a study to the EPA showing what they believed was data on how much bromate forms from sodium bromide theoretically in outdoor pool use. And the reason why bromate is undesired is because it's a potential human carcinogen. So there's limits on how much you want in the water and how much you're ingesting. So make a long story short, the EPA didn't accept the data that was provided, and they made the decision, this interim decision, assuming 100% conversion. So they're assuming that all the bromine in the water and outdoor pool use will convert to bromate, which is not uh chemically uh realistic, but that's the agency just being very, very precautious. So we did this study because we said, okay, let's throw theory out, let's

Why Stores Stopped Carrying It

SPEAKER_00 6:05

actually see what happens. And we did the study with eight above-ground pools where we treated them under various conditions. We like you said, we we let the pH go high because under higher pH, you're likely to get more bromate. And then we didn't include cyaneric acid because you know, cyaneric acid interacts with chlorine to kind of slow down some of the reactions. And we didn't want that. We wanted to see, okay, worst case scenario, what are what are we looking at? Because you might go to a pool and it might not have very much cyanuric acid, but you need to treat it right away. And maybe someone out there would treat it without any cyaneric acid in it. So we we want to see, okay, what are the limits, what are the realistic limits of using it.

SPEAKER_01 6:54

Yeah, and then of course we can tell the listeners what you found by doing that.

SPEAKER_00 7:01

Yeah, so the the kind of cliff notes on what we found was that if there's algae present at the time of use, virtually no bromate is formed. So the the algae that's present for lack of a better description, basically sucks all the chemical energy up to prevent the any conversion of bromate. So the the path to forming bromate is you know, you have bromide, turns the bromine, turns the hypobromous acid, hypobromite, and then it's believed the hypobromite forms bromites and then continues to get oxidized to bromate. And so, yeah, so when you have algae in the water, it it doesn't let the reaction go that far. And so that was using just straight sodium bromide. We didn't put, we did a comparative. So we had four pools that we just used sodium bromide, liquid chlorine, again, liquid chlorine, both is the most widely used, especially by service guys, and also probably forms the most bromate. So what we found was that under with algae, zero formation, without algae in what would be very, very clean water, you're looking at maybe 25% on average, maybe 30% conversion, nowhere near 100 and definitely less than the 50% that was often cited or quoted as being the theoretical realistic amount. So it's actually less under under those conditions.

SPEAKER_01 8:45

And do you know how the EPA tested this by chance to get their results?

SPEAKER_00 8:50

They didn't really test it. So are you talking about our study or how the EPA came to their decision?

SPEAKER_01 8:56

Yeah, how did they come to the decision? You said they didn't really test it.

SPEAKER_00 9:00

No, so the the EPA doesn't have like their own in lab, at least not really. What they'll usually do is

Testing True Worst Case Conditions

SPEAKER_00 9:10

they'll go to a manufacturer and they'll say, you go out, get this data for us so we can make a decision. They might do some in-field testing, but not in kind of this control scenario. I mean, they would have to build a lot of labs to cover everything. So essentially they're making the assumption based on an absence of data and some not directly related, but other studies out there. So they're kind of looking at everything and then drawing certain assumptions to apply it to swimming pools. So this, this, as opposed to what we did, which was actually use above-ground bundle liner pools, outdoors, Southern California, and just see what happens.

SPEAKER_01 9:56

And I think the listeners should also know that we live in California. You're in California too, Scott, right? So everything, every single thing out there from the gas pumps to any kind of plastic you get from Amazon has like a label that says warning, this is a known carcinogen.

SPEAKER_00 10:16

I don't think Prop 65, I think is that's what it is out here.

SPEAKER_01 10:20

Yeah, so everything that you buy, and in fact, I think there's some products on Amazon they won't even ship here to California because of Prop 65 because of this labeling. Again, I think, you know, just because there's a label on something, what does that actually mean? And you you mentioned EPA didn't even test this, so that kind of makes me think, you know, there was a big thing a couple years ago about trichlor tablets coming from China that weren't EPA approved. And tri-chlor tablets is basically the same ingredient as they have here in the United States. And for the most part, yeah. They stopped pulling those, they stopped selling those because of that reason. And I'm not saying the EPA doesn't have clout, and they definitely do, but you know, if they don't do the actual study, how how accurate can can that be?

SPEAKER_00 11:09

Yeah, and the so what what the process is, so it's interesting with Prop 65. When they wrote that law, they didn't have like a threshold. So, and this also goes a little bit into how EPA makes decisions, but if you don't have a threshold, then if there's technically one atom of a carcinogen, it requires the Prop 65 label. Our products don't contain that because again, there's no carcinogens in the product. It's assuming that when this reaction takes place, that bromate is formed in the water itself. So, but yeah, there's that's the limitation of like a linear model of carcinogens versus versus exposure to other models like threshold models, where it says only above a certain limit does it pose a health risk, which is something we also talked about in the announcement, but that's not necessarily our study. That's other studies out there regarding bromide and its exposure.

SPEAKER_01 12:15

I was gonna save this for later, but why is it that the hot tubs still use the sodium bromide bromine, you know, and it's not considered a violation of the EPA?

SPEAKER_00 12:28

So they they actually uh discussed that when they're making the interim decision. And the rationale was that in a hot tub, your head is above water, so you're not ingesting any water, and it's not skin exposure or anything, it's the actual act of ingesting the water that is their main concern. So if if you're not really dunking your head in a hot tub, then there's no exposure and no limitation, and so then you know you you get a pass. And they focused it on only outdoor pool use.

SPEAKER_01 13:01

That's funny. So they've never actually seen a hot tub being used by little kids, right?

SPEAKER_00 13:06

Yeah. So, but I again for for trying to, you know, I don't think anybody in the industry is a super big fan of the EPA, but the you know, these are not pool professional. They are chemists, there's chemists on their staff. They're not doing the first party data just because they can't. So they're working off a lot of assumptions. And their main driver is safety. You know, they're trying to be safe and they're trusting the opinions of others. Who's to say that they weren't lobbied by some people in the industry that are trying to, I don't know, maybe uh try to get a benefit out of sodium bromide not being an outdoor pool use. That's pure speculation, just to be clear. But, you know, those are the other potential factors. So while we don't like how the EPA went about making their decision at the same time, I don't think it's purely out of malice. They're just

Bromate Results With And Without Algae

SPEAKER_00 14:05

trying to make the best guesses they can.

SPEAKER_01 14:10

And so what's your opinion of a pool pro that's still using sodium bromide and to treat algae in outdoor pools?

SPEAKER_00 14:17

So by law, I cannot advise anybody to use the product in a manner inconsistent with labeling. So you shouldn't use yellow treat in outdoor pools if it's against the labeling direction. So that's that's essentially what I'm allowed to say. And yeah, we can't advise customers to use it. I guess you would call it off-label. That would be a violation of EPA, and we would get in very big trouble doing that. So we're not going to.

SPEAKER_01 14:52

Yeah, and then you mentioned the second bullet point that there are some proprietary formula protection in your ingredients of the sodium bromide products that you sell that actually suppress the bromate formation during the critical first hour of dosing. I don't think we talked about that first hour that was addressed by the EPA. So let's talk about that first hour of dosing. And of course, your chemicals are proprietary to your to your formula, but how does that how does that work to make your product you know counter to some of the EPA findings?

SPEAKER_00 15:27

Yeah, so so so far we've talked about the the amount that was of bromate that we observe being produced, and that was mostly by pure sodium bromide. None of our formulas are just straight sodium bromide in a bottle. We we add other ingredients to primarily improve the efficacy of the product and you know, just kind of manipulate some of the reactions. So one of the things we looked at was okay, some of the other ingredients that are used across our products, what impact does that have? And we found that depending on which formula the the ingredients, they can either significantly lower bromate formation or basically completely suppress it. The first hour is when we observed the the most bromate form. So it's it's kind of good in that most of what we found lines up with actually what the bromate work group found. So even though the EPA looked at their protocols and data and decided to throw it out for whatever their reasons are, when we looked at it, we're like, actually, they, you know, our findings are starting to align a little bit with that. And what they found was most of bromate formation happens like within the first hour. And that's what we found too. About anywhere between 70 and 90 percent, roughly speaking, of bromate you're gonna get is gonna get in the first hour. And that makes sense. That's when you superchlorinate when the sodium bromide is present, that's when you have the highest concentration. And then over time, it loses that chemical energy. It's also interesting, we didn't find in the study a strong correlation between UV light exposure, because obviously these are outdoor pools. They kind of vary in how much sun they got. Although it was fairly sunny every single day we did it. And when we took UVA readings to see, okay, how much exposure each pool is getting, there wasn't a super strong correlation between that and the amount formed. It looked more like chlorine is driving the reaction, the oxidizer. So that was what we found is that first hours when it happens, when you have these other ingredients like sulfamic acid, which is mentioned in the study, and ammonium sulfate, which is mentioned in the study, those types of things, a pH suppressant and an ammonium compound, significantly reduce the amount of bromate that's even formed in that. And we did that by doing it comparatively to just straight sodium bromide.

Prop 65 Risk Models And Hot Tubs

SPEAKER_01 18:11

And the study didn't test like any case studies of people maybe getting cancer from bromite.

SPEAKER_00 18:19

No, so the most of what's most of where this concern over bromate and why it's considered, I think it's classified as a probable human carcinogen, is from a study that started with a Japanese group of researchers back in late 90s, early 2000s, where they're feeding potassium bromate to mice. And potassium bromate is a like a leavening agent and bread. So that's so it's really a dietary thing. And they fed them significant amounts of it, and then looked at, okay, they found renal tumors. And the renal tumors they assumed, because again, potassium is something you're supposed to eat and get in your diet, they assumed it was the bromate that did it. Yeah, and that was early 2000s, and then at the time it was Arch Chemical, then did that thing that we talked about where they said, hey, we did a study, and I'm using air quotes because they basically took yellow treat and did a 66 times dose, and they came up with the 50% thing. Oh, we think we can get 50% conversion. And that's kind of what started this whole thing. Since then, and this is something that we reference, and what we're gonna bring to the EPA, a lot of people in that space that studied it have now found that they think there's really a threshold. And that threshold is anything below 15 ppm of the of ingestion is probably not carcinogenic, just because there's not enough of it in your system and your body can essentially deal with it, both through stomach acid, which gets rid of bromate, and also through antioxidants in your in your body. And so anything below that doesn't probably pose any health effect, at least according to those studies and reports. And anything above that is when you start to see the concerns. Of course, if that is true, then in a pool, the amount of bromate that's being formed is far, far less. Unless, of course, you're you know putting in tons of it, but no one's doing that in their pool. So it would essentially mean that it's effectively safe. So that's something I'm not a toxicologist, so we're gonna hire toxicologists and approach the EPA and say, hey, what do you think of this data? You know, does this change the equation? Because as right now, they look at everything linearly. So it's like if there's if there's one atom of bromate, there's some measurable exposure. But in terms of does anybody from bromate gotten cancer? I mean, if you do statistical studies, there doesn't seem to be a significant correlation like in areas that have banned bromate in food use. There's not like suddenly a huge difference in renal tumor rates, but you know, it goes back to is lack of evidence evidence, and it's like eh. It's it's hard to assess when you look at it that globally. So you would need a a statistician, which I am I am not, to to really break that down. But no, there's no no one has made a claim and there's no direct evidence of bromate causing cancer and anything other than mice when fed a lot of it.

SPEAKER_01 21:51

So I I'm gonna go back to the hot sub because I'm not a chemist and I just can't get my head around the EPA spanning this in outdoor pools. You're in a 250-gallon body of water with bromine tablets, and it's a smaller body of water than a pool. The pool's you know 10,000, 15,000 gallons.

SPEAKER_00 22:09

Right.

SPEAKER_01 22:10

There's a high concentration of bromine in that water. And how can they say that that again is safe? I know you mentioned the ingestion part, but you're just in a whole tub of this stuff.

SPEAKER_00 22:21

Yeah. So with that, the way that the EPA will say models exposure, they have something called a swim model. And what that does is it makes a series of assumptions and then calculates a certain amount of risk over a lifetime. So and we use that also in the study to kind of assess risk. And that using that model, we said, okay, based on what we found, this is what's falls into the risk exposure of what the gen generally the EPA considers safe. But that model says, okay, based on your age, frequency of swimming, and other factors, how much water do you actually ingest while swimming in a pool? When you swim in a pool, and this is kind of again, this is going to be not perfectly accurate, but kind of ballpark. You probably ingest about, according to their model, about a shot of water maybe per hour of swimming. So they say, okay. And then they look at bromate as a linear model, meaning that even one atom of that in the water, they extrapolate that risk and saying, okay, you continue to get exposed to it over 30 plus years of swimming in a pool, you know, what's your risk of developing cancer from bromate? And that's how they make their the risk assessment. But for the again, going back to the hot tubs, they're saying, well, it doesn't matter because you're not drinking the water because you're not quote unquote swimming and not dipping your head under the water. And so that kind of removes any of the riks from hot tubs. And I mean, you could argue if that was reasonable or what have you. I mean, the decisions really were about halogenated compounds. So that would be bromine, anything containing bromine. Sodium bromide kind of got lumped into that decision. So it affected not just sodium bromide, although that's what everybody's aware of right now, but also, like you're saying, bromine tablets. So I get I guess they made a good enough argument that the EPA went, sure, okay. I guess no one's drinking the water

Where To Hear Part Two

SPEAKER_00 24:45

in a hot tub, and therefore no one's going sticking their head under the water. There's no exposure to ingestion, which is the only concern, not skin or anything else. Got it.

SPEAKER_01 24:56

And of course, the second part can be found. If you subscribe to my podcast, you'll get a notification. But you can also find it on my website, swimmingprolearning.com. Go to the podcast icon at the in the banner. Click on that, and you'll see a drop down menu, and you'll see the first part and second part of this podcast listed there. And if you're interested in the coaching program that I offer, you can learn more at ProGuideCoaching.com. Thanks for listening to this podcast. Have the rest of your week and God bless.