Thank you, AOHC Stalwarts, for being here this morning. You are the true heroes today. What a vigorous audience you must be to hold out beyond that membership meeting and in a 30-minute delay here to listen to Jonathan and I yak on for a bit. Thank you for coming. I'm John Downs. For the next few months, I'm still an Army physician until I retire, so I'll go ahead and say, yeah, yeah, these are my opinions, not the Army, not the Department of Defense, et cetera, et cetera. I'm a physician in internal medicine, occupational medicine, and medical toxicology. I still work at the Uniformed Services University where I'm the associate program director for occupational environmental medicine residency. I'm joined today by Dr. Jonathan Borak, who is a clinical faculty at Yale, also boarded in internal medicine, occupational medicine, and toxicology as well. So again, no disclaimers or disclaimer for the military purposes here, and no relevant financial or organizational interest to disclose this morning. We're going to be talking about safety data sheets, a little bit about the hazard classification criteria that are in there. I want to highlight some of the chemical and physical properties that might be useful in predicting routes of exposure that you might find off of a safety data sheet and what portions of a safety data sheet might be relevant to acute and chronic health effects. Notably, I'm going to make mention of limitations there of these, which I think became a larger portion of my consideration as I started developing this presentation. So they've been affiliated with occupational medicine in some form or another for about the last 10 years, and I recall even in my training and as well as in training others now that, well, if you have a worker who's been exposed at your workplace and they come in for a reported chemical exposure, then one of the things that you want to ensure that they bring along with them is the safety data sheets from wherever they're working at. So in the safety data sheets themselves will also say, if you have an exposure, you should notify a physician and bring this along with them. And I thought to myself at one point, and apparently Jonathan had had the same thought, has anyone ever told us what to look at on a safety data sheet or discussed if there is even valid information on there for which a clinician might use? So hence the discussion for today. If we're going to recommend people bring these in, well, one, should we? What's their utility there? And as a clinician in occupational and environmental medicine, we should have some brief at least understanding of what should be on there. So Jonathan is going to cover a little bit about the history of the formerly referred to as material safety data sheet, now referred to as safety data sheet, because it has been an evolution over the last 100 plus years. We're going to give a couple of example scenarios and then highlight some limitations within these. So we'll be using two relatively well-studied, at least within occupational settings, chemicals, and then sort of see if the SDS mimics what we think it should based off what we know about those substances or if that we are left wanting in some cases. So Jonathan, if you'll come up here. Great. I hope I get this to work correctly. I just want to introduce you to the very concept of conveying information. And let me start by saying, as most of you know, the MSDS or SDS has significant limitations. And the question is, on the assumption that most of us in the room are caregivers, the question really is the relevance of the SDS to the interface between us and our patients. There has been an effort over the years, it's now 100 years long, more than 100 years, in trying to convey information about occupational exposures of potential harm. As far as I can see, going back to a formal structure, the origin of this kind of philosophical undertaking goes back to Metropolitan Life, which was at one time the single most important insurance company from the standpoint of workplaces and workers, which published a series of books starting in 1918, which were then adopted and co-published by the U.S. Department of Labor and the U.S. Navy, which was referred to as the Occupational Hazards in Diagnostic Science and was provided gratis to physicians and included a number of very specific identified chemicals which were referred to as poisons. And it's important because the concept of what an MSDS covers, SDS covers, and these differ. SDSs cover a huge number of commercial mixtures and chemicals, and this was really focused on a narrow view of things that were particularly noxious and toxic. But you can kind of see the evolution from 1918 to 1942, in which it went from 34 poisons to 128 poisons, and it's useful if you find a copy of this book in your libraries to see the kinds of things that they were concerned about. Many of them we're still concerned about, like carbon monoxide, benzene, and arsenic. The MSDS has a more specific history, beginning in pre-1983 when it was a voluntary program championed by largely the Chemical Manufacturers Association, which was not what it called itself then, in an effort in part to avoid federal mandates. It did not have a standardized format. It did not have particular requirements. In 1983, OSHA promulgated the Hazards Communication Standard, which required that there be such an informational document available that was covering certain specific data types, eight standard fields. It addressed hazardous chemicals specifically, and it considered mixtures, and it identified a mixture which was to be included on an MSDS if it had at least 1% of the mixture was a hazardous chemical, or at least one-tenth of 1%, which was a recognized carcinogen, okay? So suddenly, the scope was enormous. We were talking about mixtures which could be fantastic in terms of the numbers and variety. In 1987, the Emergency Preparedness and Community Right to Know Act, SARA Title III, or EPCRA, was promulgated by the Congress. It required under EPA that MSDSs be available to identify the chemicals which were covered under EPCRA, and for the purposes of communicating between plants and communities under the community right to know, which was the rubric or phrase that was used to describe this effort. And so MSDSs became then required under both OSHA and under EPA under separate regulations, separate laws, okay? And then there became an industry which generated MSDSs. This was pre-internet, so it was a little harder to find them all, but there were numerous companies that were preparing these with variable levels of adequacy and review. It continued in that kind of an ad hoc way. It wasn't ad hoc in the sense it was required, but it was ad hoc in the sense that they weren't being reviewed. In 2003, the United Nations adopted something called the Globally Harmonized System, which established a more uniform format and content structure and expanded from eight to 16 data fields. And that particular format was adopted by OSHA in 2015 so that SDSs replaced MSDSs, although I frankly am ingrained in my head and can't say it without the M, and expanded the length of the document, okay? None of this addresses its utility to those of us who were clinicians or caregivers or even program planners because it had the same uncertain information, okay? But it was more formally structured and more recognizable. So let me go very quickly, I'm going to do this very quickly because I'm going to go through these slides again, telling you ones I think are relevant to us. But there were 16 SDS fields of data, product ID, emergency classification, composition and ingredients of mixtures, first aid measures, firefighting measures, accidental release measures, handling and storage, exposure limits, physical and chemical properties, stability and reactivity, or is it going to explode or ignite, toxicological information of a variety of sorts, not all terribly relevant to you in the first interface but at various points along the line, and then ecological information, disposal information, transport information, regulatory information, and the date of the SDS preparation, okay? It's a lot of information. The question becomes which of these are relevant particularly if you are in the situation of either A, getting a new patient in your clinic or wherever you see patients who presents this to you, in which case really what it's doing is simply identifying the exposures of primary concern for the worker, or in the state of emergency or semi-emergency sort of situations in which it is a very quick way in which you can identify the likely causes of the emergency, and so it's a first cut. So now, on those data fields, the composition and ingredients is clearly the single most important piece of information on the SDS. If you go up to a number of different sources, Google is as good as any other, and put in the name of a common chemical and start to look for all of its synonyms, it's awesome. The number of synonyms for benzene is just long, long, long, and so it is, if you don't normally think this way, the chemical abstract service number is a wonderful unique ID for each chemical. In fact, different ID numbers sometimes, if we're talking about racemic isomers, which may have variable degrees of toxicity or other harm, you can search Google, you can search PubMed using that CAS number, and gives you very precise information, and it's also extremely useful in conveying certitude in your communications to people. I mean, if somebody asks me a question about a chemical, I try like hell to have them identified by CAS number, so I know that I'm not wasting my time, okay? And mixture ingredients are terribly important, and oftentimes not adequately described, although they should be, on the SDS. First aid measures, obviously. This is useful to you if you're dealing with an emergency. They are often very superficial. They will tell you whether to vomit or not to vomit. They will tell you to clean the patient, which is almost standard and unthinking, and it may give you some quick insights into symptoms. It's worth a quick look, but hardly worth rereading. The physical chemical property is a long list of which very few are immediately, and even over the shorter but not chronic term, of relevance to you. The odor threshold of a chemical is extremely useful simply because it's a warning property, and for some chemicals, it gives you a first approximation of the level of exposure. For that, of course, you need to know what are the odor threshold, and if it can be smelled, you know you're over it. I mean, this is stupid, but it's obvious and useful. The pH is relevant to different kinds of injuries, both respiratory and others. If you went to the World Trade Center conferences today, you've read about it, you know much of the injury was related to the caustic alkalinity of the mixture, and so on. Vapor pressure, vapor density, extremely useful for two reasons. Vapor pressure tells you whether a liquid is going to migrate and disperse or stay in place, and vapor density is going to tell you whether to walk tall or crawl on your belly. Okay? If the vapor density is a low number, it means the stuff is lighter than air. You can crawl and duck it. If it is heavier than air, with a number greater than one, then you've got to be very careful staying out of the basement, for example, and so forth. Liquid pressure, which we will talk about, is one of those things, it's really hard to get a feeling for what it means. The vapor pressure defines the point at, helps to define the point at which a liquid boils. But it doesn't have to boil to meaningfully vaporize and become dispersed in an area, and also of importance is the area. For example, mercury, whether it's at the Smithsonian or anywhere else, if it's in a closed space, although it has a very low vapor pressure, can achieve a very toxic concentration. The value of vapor pressure of 10 is relatively low, remember 760 millimeters of mercury we think of at standard temperature and pressure as being a boiling point. You don't have to be that high. If you have a vapor pressure of 10 or 20, it can generally result in a fairly large amount of vapor formation at room temperature. So you need to be careful. The low ones, sulfuric acid, 0.000 something, and as a consequence of that, the TLV for sulfuric acid is based on its capacity of its particulate bubbles in air to etch your teeth. But you don't actually inhale the vapor. It's the dispersed sulfuric acid as droplets at any rate. This goes to show simply that we've got three different chemicals and we're showing you three different vapor pressure curves simply to indicate that each chemical has its own. And the point of importance has to do with two things, the vapor pressure and the temperature at which you find yourself. So clearly the higher the temperature, the more it vaporizes, the colder it is, the less. And it's useful to get a feeling for it. How do you get a feeling for it? You look up 20 different solvents and write their names down on one column and in the next column, write down the vapor pressures. You can get out of the NIOSH pocket guide to hazardous chemicals as a reference point. And you start to see where some of these vapor pressures fall from high to low or from low to high and it starts to give you a little bit of a gestalt feeling for what it means. Still its biggest use for you is to know whether things were going to disperse and how they're going to disperse high or low in the area. Vapor densities greater than, less than one, lighter than air. Vapor densities greater than one, heavier than air. Here's an old mnemonic that goes back to my early days in learning toxicology, ha ha mice. And it helps you just to remember, because it's hard to forget this stupid thing, that it's hydrogen, ammonia, hydrogen cyanide, acetylene, methane, aluminum gas, illuminating gas, which was sort of a methane like substance, carbon monoxide and ethylene are all lighter than air. So there's a difference between an ammonia release and a chlorine release at some work site is that the ammonia is lighter than air and a big white cloud cliffs up in the air and the ground level remains generally safer. And chlorine is heavier than air and if you see pictures after a tanker rolls over and stuff, you see these green clouds in the areas where the land is below level, okay? And this is just a first approximation, it's not going to get you through your boards, but whatever, you know, there you go. The toxicological information is fairly, potentially quite descriptive, roots of exposure, symptoms related to physical, chemical and toxicological characteristics, delayed and immediate effects, chronic effects from short or long term duration, numerical measures of toxicity, such as acute toxicity estimates, LC50s, LD50s and those kinds of measurements would tell you about animal deaths usually because they're very little data of this sort that come from human studies and it's carcinogenicity ranking usually National Toxicology Program, IR or OSHA. The problem with this section on most MSDSs is it requires a fair degree of sophistication to do it right and so a lot of mechanically generated MSDSs may be very extensively missing. There you go. I'm going to stop now and let John take over. Thank you, Jonathan. Sir, we'll do a little bit of an illustrative case scenario here, you know, somewhat facetious, but we'll use it for illustrative purposes. So I think most of us in the room would be familiar with methanol as a chemical, so we're just going to say that you're not as familiar and there's a lab accident and there's a spill of several gallons of methanol. There's nobody that's acutely injured, but you want to know a little bit about methanol, so you're going to go to the SDS and, you know, try to quickly inform yourself of potential chemical dangers and, you know, we're fairly well described methanol as it will eventually induce blindness to see a CNS toxicant. You can get basal ganglia effects with severe poisonings, even hemorrhage into the basal ganglia. It's unique as a toxic alcohol in that not only does its route of exposure include ingestion, but also even inhalation of methanol in workplaces have led to toxicity. So this is one, there's been a fair amount of information about, we would think then that the SDS would be able to provide us with a fair amount of information here. So we'll look at section two and section four, as Jonathan alluded to. Section two is the hazard identification sort of quick look section here where you'll be able to, in most cases, see a pictogram of some sort, at least give you a rough idea of the categories of things, and section four is our first aid. So again, this is an SDS drawn from what I would think is a fairly well-known and reliable chemical company, so I'm just taking snapshots from them, not naming them to see what they have on there about methanol. Looking at section two, we've got a couple of pictograms here that's part of the global harmonized system. Ideally, the SDS should have a pictogram on there, so even if you don't immediately have it or are able to read the language that's on there, you could at least see that. So the first thing that's listed is its flammability, which gives you category two. Does anyone have any idea what category two means for flammability? Nor did I, which is why we are here. If you really want to go nerd yourself out at some point, there is the very, very lengthy appendix to the HASCOM standard. Appendix A and B explain how these categories and numbers are generated and what they're intended to mean. Methanol falls into category two there, roughly meaning that it has a relatively low flash point and a relatively low boiling point, so it is likely to catch on fire with limited sparks even at room temperature. Categories are just delineations. They don't necessarily help us, per se, in a particular scenario, but at least it gives us a quick sort of idea of, okay, this is more flammable than some other compounds that we might run into. Jonathan and I, and presumably most of you all here, are interested in the toxicity piece. So we got a skull and crossbones there, my favorite pictogram all over my home office, and it says it's a category three acute toxicant for oral, dermal, and inhalational purposes. Again, I had no idea what category three meant for that or why that should be important to me. So you go, again, dig down into the appendix of the HazCom standard, and it breaks down a table of exactly what category three was intended to be. Now, all of this data are based off of, for the most part, animal models, LD50 and LC50, or lethal concentration for 50% of a population animal data. I always find that a little interesting that we publish those values, because I don't think we would ever feel comfortable with saying, well, that's a value that'll only kill 50% of my workforce. So that's good enough. Ideally, we would want something closer to LD1 or below. We could talk about what that means on a dose response curve, but this is what we get, because animal models and times are limited. And I'll note here, this says category three. Again, it's really just giving you a sense of is this fairly potent toxicant or not. It doesn't necessarily tell you particularly about the situation that you are inheriting at that time. And I'll even note here that with this one, again, an SDS from what I thought was, or think, is a fairly reliable chemical company. I'm not even looking at this data myself. I didn't see why they put this in category three. There's a fair amount of human literature about methanol intoxications and outbreaks related to illicit ethanol use. And the LD50 approximated there somewhere in the thousand milligram per kilogram for humans, so that would put us in category four. The inhalational values are well up into the thousands for LC50 for methanol. So again, that would put us in category four. I'll also note on here, it's a little bit different for a lot of us in occupational safety and health. What units do we usually think about for air concentrations? We get parts per million air, or what? Yeah, micrograms per cubic meter, but what's on here? Milligram per liter, and I looked for a while. I couldn't figure out why that value was referenced that way. I think it has just based off of the way the animal models are created, but this is always a trivia question for me. I'll throw it. Anyone know how many liters in a cubic meter? Of course you know, Michael Holland. Yes, so as hard as this is for me to conceptualize, yes, there's 1,000 liters in a cubic meter, which I always have a hard time wrapping my head around, but that is true. And there's roughly what they're getting at here between vapors and gases on there. It's sort of approximating whether this is more of a mist in the air versus a true gaseous state. So it's also a little bit hard to state from that, you know, which of these values should I really even use? Then they denote specifically a health hazard, which again, this is very important to us. You may see two different comments on there, an STOT SE or an STOT RRE. That's a specific target organ toxicity for a single exposure or specific target organ toxicity for repeated exposures. In this case, they note that it's a category one. Well, again, what does that mean here? Category one are defined as by the global harmonized system and thereby also by the OSHA-HASCOM standard. Category one for STOT SE are things that we know have human toxicity, that there have been incidents of human toxicity before well-described or there's fairly significant evidence in experimental animals of a significant toxicity. We just drop down to category two. It's more presumption based off of animal models and category three gets to much less clear. So again, not the greatest like ability to discern over to a direct patient, but at least it gives you some sort of sense that if it's an STOT SE label as a category one, yes, this is in theory, should have significant literature or data to support that there has been significant toxicity in humans. And that makes sense for methanol as well described occupational and environmental and public health toxicant. Looked at section four here, the first aid measures. As Jonathan alluded to, you're probably not gonna get a whole lot of fulfilling information out of this. What seems to be the case as companies have gotten more into either sort of drop down menus to create SDSs or contracting it out with SDS creation organizations or companies, it just seems to be sort of a drop down menu and pick standardized things here. Yeah, so get medical assistance. Thanks for providing us with that. Don't know if we would have moved quite there, but as Jonathan was saying, otherwise it's fairly limited information in terms of what we should do for dermal exposure or eye exposure. I think all of us would at least say, yeah, wash it off, external decon, that makes sense. I'm not even sure that I would agree with the having individuals drink sips of water if they had ingested methanol, but here it is on there nevertheless. When it gets to reported health effects, and again, there's a wild paragraph here. There seems to be some reasonable statements in there. Yes, it's toxic by ingestion. We know that. Also toxic through dermal and inhalational exposure. Again, this is sort of unique amongst toxic alcohols that methanol is well-described toxicity even with inhalation. It does at least note that there could be potentially irreversible effects. I agree there. If you hemorrhage into your balal ganglia, that's not a good day. If you go blind, also not a good day. So at least we've got that noted. The rest of it is a little bit vague and not all that helpful. Again, standard disclaimer though of, yep, provide your SDS to your physician. Your physician should treat symptomatically. Not sure that's particularly helpful either, but again, workers think that this is what they're supposed to do, and most of us have been told throughout our career that the SDS should be brought to you, and perhaps there's information on there that we could glean to be able to treat the patient. So even with a fairly well-described chemical toxicant and from a fairly reputable chemical company, we can see that there's inconsistency even on their documentation for an STS. And if you pull STSs from various different companies, you'll see inconsistencies amongst the safety data sheets from one to another. Despite what initially, earlier in my career, I thought that there would be some sort of standard generator for this that would be able to have consistency amongst products. That's really not the case, and you may find that companies create SDSs based off of a simple Word document template that could be given really to any employee in their company to utilize without any real background in toxicology or even basic chemistry to understand. So what they put on there is what information they have at the time. In the United States, there's no requirement that this toxicologic testing really be done prior to a chemical being released by a supplier. So if they haven't done testing, it may just say no information. Even if there is data that's about that particular substance may still say no information. And there's been a realization over time that it is expensive for these to be maintained, which again, it doesn't seem like a big thing to maintain a simple document to update the information on there. But not only is it evolution of science, but also evolution of regulation. If you're a multinational company, you also have to keep abreast of what regulations changes are happening in all those other countries and then update the safety data sheet to go along with that. So there's been some estimates of somewhere on the order of depending upon the chemical company anywhere between 100,000 and as much as $300,000 a year if you're a large international chemical company just to maintain safety data sheets to try to keep them accurate. And as Jonathan alluded to, there is sort of an industry now that's come out of that to focus on creating safety data sheets and have companies contract out with them. If you have the information, I've seen estimates of about 16 hours to create a new one. Again, that's assuming that there's quality information has went into that. So if you can imagine a larger chemical company that has dozens or hundreds of chemicals, the number of man hours per year that would be needed to update that. A lot of what we have discussed already this morning and limitations has already been acknowledged in the chemical literature, but I don't think it's really got across to healthcare professionals. There's a couple of good papers I've referenced there from 2022 in the American Chemical Society sub journals talking about the problems that chemists have with safety data sheets and laboratory folks have with those. One thing that's been noted on there in particular that one of the papers mentioned was, who knows what, picric acid or trinitrophenol. Pam is shaking her head. It go boom, it go boom real big. You know, it's one of the primary explosives during World War I. And so one of these papers was referencing that their lab had received shipments of picric acid where the SDS said not an explosive hazard. Yeah, despite it being used as an explosive. I think it's difficult when we try to make documents that are intended for a variety of different audiences. So it's hard to speak to somebody who is a safety professional at the same time, speak to someone who has a medical background or even a more formal toxicologic background or chemistry background. Anytime there's novel chemicals or mixtures, we still have a hard time handling mixtures in toxicology and what does that really mean? How do those things interact in vivo and in vitro? And even now there's been discussion of, should the SDS include like downrange effects? Meaning if it sets on a shelf for X period of time, what does it degrade to and what's the hazard of that? Or chemical interactions that may not be listed out on there that could lead to explosives or the generation of other hazardous toxicants. And there's been a couple of papers recently noting that if you review several hundred SDSs, that somewhere on the order of 30 to 50% of them will have overtly incorrect toxicologic information. So yeah, you're getting a document that I believe, as Jonathan would say, winds up becoming more of a legal document intended to suffice a standard rather than something that is really meant to be helpful for you as a medical professional or a safety professional. So I'll just introduce quickly, like again, we thought we'll take a look at another fairly well-described chemical. So now you're gonna work at a company that's producing viscous rayon, so you're getting involved with carbon disulfide. Again, well-described hazard over the last 100 plus years of occupational medicine. And so maybe you don't know though, you think a good idea to take a look at the safety data sheet before you guys get started. And you wanna take a look at what information you can get from there to inform you. And again, pulled these safety data sheets from a fairly reputable chemical company to sort of see what they say and hopefully that we'd be able to find some information that would be useful for us. And Jonathan will take you through what we found with this carbon disulfide. Thanks. Well, I was very grateful for John for picking carbon disulfide as a topic because it illustrates something which I couldn't have imagined off the top would be quite so compelling. We there, okay. So the classification of the substance, it is flammable, it has toxicity, it's an irritant, eye irritation, common symptom complaint, reproductive toxicity, specific toxic organs, particularly neurological system. It's good to know, not terribly informative, but at least it gives you your orientation. First aid measures, this is an amalgam of four different MSDSs. I took as a default, if there was any information, I've included it, okay? So I don't want you to think that I was looking to stack this deck. First aid measures, none. Accidental release measures, nothing. Exposure controls. This is a list of the various limits that have been established so that you've got a sense of 10, 20, up to 100 ppm for different purposes. Here you've got the physical properties. Odor threshold, it's described as having a very characteristic odor, but it doesn't have an odor threshold. So whether you can smell it or not is terribly useless. It is dense. And beyond that, there's almost nothing there that's useful to you. Here's the toxicological information. This is from four different MSDSs from major firms. There's no acute toxicity data. There's no skin toxicity data. There's no germ cell mutagenicity data. There's no reproductive toxicity data. And there's nothing about single or multiple exposures with specific organ systems. Although it's well reported in the literature to have certain specific targets, okay? It's rather appalling. Essentially, this is a family of MSDSs which are essentially of no utility, okay? So the question is, what could I do that would be useful to you? I can't talk about MSDSs. I've just told you, they're lousy. And I can't talk about carbon disulfide based on the MSDSs because they are lousy. So let me tell you about a different resource. It has some potential utility and you should at least be aware of it. And it's something which was referred to as acute exposure guidelines developed by a consortium which included the National Academy of Sciences, a standing committee that spiraled out from the American Industrial Hygiene Association, and a board of scientific advisors that included most of the US government agencies and probably 20 different foreign countries by the time it was done. It was developed largely for the purpose of trying to establish whether to evacuate and where to evacuate or whether to shelter in place coupled with gas dispersion modelings that can let you know when a release is going to reach certain levels and how long they will remain and so forth. There is a software program called Cameo that's on most emergency response vehicles which can help to model that. And so most commanders of hazardous materials response teams have that kind of data. But the AEGLs are a series of documents. They are a remarkably good data source when other data seems sparse. They're extensively peer reviewed by EPA, by advisory committees, by the National Academy of Sciences and others. The numbers that they promote are almost never on an SDS. It includes 188 gases specifically listed, gases and volatile liquids. And here's a website where you can find all 188 documents. I would urge you to take that one link home and stick it somewhere where you can access to it. And let me explain what an AEGL refers to. It was developed by EPA between 1995 and 2011. It was derived originally from the AIHA's Emergency Response Planning Guidelines. And it describes exposure effects in three levels. Cleverly, AEGL-1, AEGL-2, and you want to bet AEGL-3. AEGL-1s describe levels of exposure which are associated with notable discomfort, irritation, and certain non-sensory effects. AEGL-2 refers to levels that result in impaired escape or irreversible adverse effects. And level three are those associated with life threatening. So now we've got these three. But now we're talking about a concentration dependent effect. I mean, a dose response curve. that's what we're really getting to. And in this case, a dose-response curve is defined as dose in terms of concentration in air over time. And that is something which is generated by these dispersion models. And there are five exposure durations considered by the AEGL system, which includes exposures from 10 minutes to eight hours, which explains how it helps to understand whether you should evacuate. If you only need to stay in place for 10 minutes and then you can leave, it's no sweat. It also tells you whether you've got to stay and shelter in place for eight hours, because it's a problem. Not always at either extreme, but it's useful to have a sense of dose as this provides it. And here we're talking about carbon disulfide. Now, carbon disulfide is a neurotoxicant. It can cause death. It can cause peripheral neuropathies. It also has some effects on the liver. It reduces alcohol tolerance. It has a wide spectrum of effects, which have been documented. The problem is, I've just shown you four MSDSs that don't essentially even mention that. These AEGL documents are based upon extraordinarily meticulous reviews that were done by the toxicology group at Oak Ridge, Tennessee, which includes virtually every documented report which might be relevant, both human and animal, described in terms of both end organ effect and, to the extent that it can be known, dose. And it's rather concise. I mean, under the circumstances, it's not a very long read. I've got the carbon disulfide documents sitting underneath my phone there, and it's really only a half a dozen pages, if you're interested. And it's useful, and it's available, and the price is good. It's free. So the AEGL-1, this is the point at which the exposure is obnoxious. And here you see the levels that have been determined for exposures of 10 minutes running out to eight hours. It gives you a ballpark, okay? It's relative. Everything's relative, but it's rather much more specific than you'll ever find on a TLV. Here's AEGL-2. This is the level that's associated with either the incapacity to escape or irreversible adverse effects. And that gives you another dose metric, which is useful, not definitive, because you don't always know what the level of exposure was that your patient or group have, but it gives you a gestalt. And finally, what are the levels of exposure that can do you in? Now that's what we really want to know in a rapid review when a patient comes into you, whether it's an MSDS or SDS or some other equivalent information. You want to know, one, what is the chemical? You want to know, what is the likely effect that the chemical might have? You want to know something about what is the dose relatedness, and then you have to figure out what you can tell about the dose of exposure to which your patient was subjected. And then from that, you can start to figure out what you have to do from a clinical standpoint. I share with you this AEGL document series because it's extremely useful, and one of the things to know is there is almost no current research being done on these chemicals for a couple of reasons. We can't subject people to them. Most of the exposure levels have been lessened in this country. You might find third world countries where exposures are being reported, but there are few. And there's a large move away from animal lethality studies. So this is a literature which does not age quickly. And it's a reference source which is rather useful. So I share it with you in the hope that it provides you an alternative and something to talk about if you have nothing else to do with your time. So if I finish up just summarizing, we've gone over a little bit of chemical and physical characteristics of substances that you might be able to glean from an SDS that would help you better understand the chemical hazard, in particular vapor pressure, vapor density, octanol water coefficients for lipophilicity. Those things can help you understand where a chemical might go in its particular route of exposure. We understand the medical information there is going to provide very minimal initial management guidance, but despite what some might have been taught or even what the SDS said shouldn't be counted on for definitive treatment because there's inherited limitations and weaknesses that must be utilized for workplace decision making. I will note, not that I intended this, but it just so happened as I was looking yesterday, lo and behold, there was a final rule issued on just Monday of this week from OSHA to update the HazCom standard. Incorporating a little bit about what we've talked about today, I don't think this will come around to fix the problem of the inherent limitations with safety data sheets, but this is intended to now incorporate the seventh revision of the Globally Harmonized System. However, the rest of the world, the GHS is on the ninth and about to go on to the tenth, so we're a little bit behind, but some of the things that were supposed to be encouraged through this update are additional annotations about explosive reactions, interactions between other chemicals, and these sort of downrange products, and I believe this goes into effect in July, so in theory, companies should be coming into line with this and trying to update their safety data sheets, but again, this was a 256-page document from the Federal Register that I found at 2100 last night, so forgive me that I didn't stay up all night reviewing every piece of it, but you're welcome to, should you have nothing better to do for the next two days. So I'll take your questions. We've got a few minutes left before the next, and I think I'll prompt my own first question, which is, well, John, if these things are terrible, then what am I supposed to do at this point, and what am I going to look for as an alternative means? I think at this point, for acute, I come from a MedTox background, if it's acute exposure, I think poison centers still have a role. We have some other data sources that we can utilize independent of the SDS that may help you. I think if you're in a situation where you're planning, then probably looking at SDSs from a couple of different companies to compare, as well as doing a little bit of your own review of individual chemical components, and seeing if you agree with what's been placed on there as part of your emergency response plan and management for these situations. And again, we'll take a few minutes for questions now. Dr. Uneskevich. Good morning, gentlemen. Thank you for a great talk. My background, a Navy OEM physician. For better or for worse, I've had the opportunity in my career to be asked to respond to a number of environmental exposures, a lot of town halls, a lot of discussions, and what I see with issues with the SDSs is one of risk communication. And oftentimes, trying to reassure a population and getting documents like the SDS thrown in your face as this is why this is going to kill me or hurt my children. And so I appreciate, one, the reference for AGLs. I think that's useful. If there's any other resources out there that we can use to, yeah, the SDS is good for hazard identification, but there's also the flip side of that when we're trying to reassure people that they're okay. Sometimes the alarmist nature in the SDS and the inaccuracies, inconsistencies can sometimes can lead to difficulties. So that's just a statement there. Earlier, sir, you mentioned odor threshold as a warning sign. Another area where I've had difficulty is where the odor threshold is lower than any action level that would need to be taken. And so trying to reassure somebody that while they can smell it, they're still safe. I was wondering if you had any recommendations or maybe some insight in how to approach that. My first recommendation is that you check what the odor threshold is and compare that to the toxic level. And in many cases, the simple statement is that there are no warning properties. So I would certainly not tell somebody that because they cannot smell it, they are safe without having done that would be a foolish thing. I think his question was that if... How do you reassure them? If the odor threshold is well below an air concentration that is presumed to be toxic... Oh, I'm sorry. I got it the other way. If you're saying if the odor threshold is very low, then you can certainly tell them that the fact that they smell it does not imply that there is any risk. But now you don't have a definitive sense of how much concentration there is and you need to measure it. I would agree with that. At that point, they're just identifying the hazard. You would have to do some other quantification to then to be able to feel comfortable saying that the value hasn't been exceeded some toxic value and isn't just staying there at the odor threshold concentration or just above that. But it's certainly difficult then because it's hard to convince someone that something they can smell isn't at a concentration substantial enough to harm them. Very briefly, there's another problem, which is there's a concept of odor fatigue. There are certain chemicals. The classic one is hydrogen sulfide, which smells like rotten eggs, but its first toxic effect is paralysis of the olfactory system. The fact that the odor disappears is in no way a reassurance. It may be an indication of the onset of toxicity. It's mainly a warning sign, which can be useful, but it's limited. Mark Bodo, Seattle. I do independent medical evaluations for the state of Washington and all around the state, and I have a considerable number of claimants coming in with various claims about chemical exposures. Most of the time, they don't know anything about even getting a safety data sheet or asking for it, and occasionally, the employee with some complaint of exposure will ask for it to management, and they refuse to give it to them. My understanding is that this is federal law, that if you ask for an SDS, you've got 72 hours to give that to your employee, and I think that was under either TOSCA, T-O-S-C-A. I'm not sure if that's still in existence in the federal right to know, though. Then even after I request from the company, I get some resistance even to get their safety data sheets, but I can look it up in Google, whatever. There's an issue about employees not knowing about this, and then refusal from management. It's kind of crazy, so I just wanted to make that comment. Yes, so within the HASCOM standard for emergency situations, a healthcare professional should be able to call the company and get an immediate release of that information, as well as any proprietary information, and I will make, then, the comment, in theory, most safety data sheets will have an emergency call number at the top of them. Frequently, they're referencing the ChemTrek company. About a month, maybe two months ago, I called, because I had an interesting question that had come in while I was on Poison Center call, and I called the ChemTrek number, because that was what was listed on the SDS, so I'm just telling you this anecdote, another sort of limitation here. When they rang, they picked up right away, and they asked me what I was looking for, and how they could help, and then I told them what it was, and they said, that's not a company that's contracted with us, but frequently, now, companies will fill out the SDS and put our 1-800 number on there to just fill in the blank, so we don't know anything about that particular hazard that you're concerned about, and there isn't an alternate number on there. I recognize that certainly is a problem, and I'm not sure that the OSHA enforcement folks have enough time to really address down to that level. Is there any way to get around where there's proprietary information, and they're not going to release it? You got something that you really need to know about? Is there any way to circumvent that? Not that I'm aware of. Again, in theory, by law, if it's an emergency situation, and if it's a non-emergency, there is a HANSCOM standard they're supposed to release upon written request, but again, that goes into legally encouraging somebody versus just, I guess, expecting people to be good stewards and taking our calls. Yes, sir? Thanks for an excellent presentation. So I'm surprised you didn't mention the ATSDR TOCS profiles and TOCS facts and the public health statement, because personally, I found them extremely helpful and also accessible oftentimes by lay people. So I think that's... Thank you for adding that. That's a great resource if folks don't know the ATSDR TOCS profiles. You got to be careful which one you pick if you want the 700-page compendium of all of the data of which you could find every animal model done in there. But I think the summary documents that are a couple of pages there are a great quick reference for individual chemicals to get you in the right ballpark there. So the other point I wanted to mention is that it's very helpful when you know the specific chemical that people have been exposed to. But as often as not, a worker comes in and says, I don't know what I've been exposed to. You ask the company to send you the SDSs and they send you 483 different documents. So one of the resources, I'm curious about your sense of the validity of it that I've used when you can look up an industry, a process, a task, a job for it is HAZMAP. And I just wonder what you think about the validity of what you can find on HAZMAP. I actually checked that again last night. If folks aren't familiar, I believe you're saying the HAZMAP, H-A-Z dash M-A-P dot com. So that was a online resource created by an occupational medicine physician. You don't happen to be him, do you, sir? No. Okay. That originally was a contracted thing that then the National Library of Medicine via the National Institutes of Health took over and managed for a while. It is a pretty nice resource in that, and I'm sorry for sake of time, I'll have you as the last question and I'll go to the back because I have others coming up to speak here. But it's a nice resource where you can actually search by occupation, by particular chemical of concern, by product of concern, and it'll give you information, sort of get you in the right wheelhouse. The one downfall I would say for it is I'm not sure how well it's being updated at this point because the National Library of Medicine shut down their Office of Clinical Toxicology in 2022, and it, I don't know if it went back to its original proprietary owner to update or, at one point they were looking for somebody else to like buy it and take it on as their own project. Sir, if it's okay, I'll take your questions in the back so we can go ahead and get started with the next. Hi, Matthew Krebs. I'm an occupational medicine physician in the chemical industry for about 27 years now. I've spent literally thousands of hours writing our SDSs for our company. Understand that the SDS is a hazard document. It can't cover the risk, and that risk assessment has to be done outside of the SDS. So we have to list all of the possible hazards, and we try to do that the best we can. The GHS standard document is over 800 pages long of conditional logic telling you what studies to use, what criteria is to use, and they provide very prescriptive language for the sections that you pointed out that appear to be not very relevant. If you read the 800-page document, it is a very elegant system for communicating the risk or the hazard that's present. So if you see a health hazard one, that is the most severe health hazard, and that's something that you should pay attention to. If you don't see any health hazards, it means that we haven't seen anything in human studies or animal studies. The first aid measures are just that, they're first aid. We give you the information that a first responder or somebody on scene can do. And so that's why those are like that. The notes to the physician section for companies that have physicians that are writing these, we're not a healthcare entity, and we're not allowed by statute to prescribe treatment, but we do give you information where there's alternate therapies, where there are therapies that may not be proven. I do agree that not all companies take the time or the care to do these properly, but those of us that are in the chemical industry that care about the proper use of our chemicals to enhance the lives of our people, we spend a lot of time, a lot of money, and a lot of effort, and it is a very complicated process to do. So please, when you describe it, look for the value that you can get out of it to understand at a quick look what are the things I should be looking for. If I tell you to treat symptomatically, it's because what I'm telling you is there isn't a therapy that's been described, there isn't a specific data, and the ABCs are your most important thing. So if anybody wants to discuss further, my name is Matthew Krebs, and I do work for a major chemical company. I certainly appreciate the work you do, then, in trying to get it right, so no slings or arrows at you. I think we're mostly focusing on things where people don't make the sort of diligent effort that you do. Again, I apologize for cutting things off here. We've got to start our next session now, which I am also moderating. So appreciate those who have been stalwarts and are sticking around with us. Thank you all. Thank you, Jonathan.

safety data sheets

SDS limitations

chemical exposures

healthcare professionals

emergency response

Acute Exposure Guidelines Levels

AEGLs

ATSDR TOX profiles

risk assessment

hazard communication standards