DIP Episode 657 - OMBRS 3-The OSHA Silica Standard

All right welcome my name is divine this is episode 657 of the divine intervention podcasts and today's podcast We're gonna be continuing the series On occupational medicine board review and again, you know, we've done the OSHA lead standard OSHA As best-to-standard it was a pretty high-yield and we're gonna do another pretty high-yield standard called the OSHA crystal line Selica standard, right? So again, I'm gonna talk about a lot of things that I think are very important to know for your for your exams, right? So let's just jump kind of jump right into it, right? So Again, we're gonna focus on the OSHA crystal line Selica standard, right? They love to test this on the exams. It's on the Ahmed exam blueprint. You got to know this stuff, right? They love to test this. It's a very common hazardous exposure. It's a very common occupational long disease So if you're sitting for the boards, you want to make sure you know this stuff and you know this code, right? So Let's start with some context, right? So the thing is crystal line Selica is one of the most abundant minerals on earth, right? You'll find it in quads, you know, which makes up a pretty big chunk of the earth's crust, right? You find it in crystal-balight and tritamite, right? And those are higher temperature forms of Selica that you encounter in a lot of industrial processes, right? So the thing is when you rock or concrete or break or mortar, you know, his coat is ground is drilled It's blasted.

It generates fine respirables Selica particles, right? Those particles are the hazard, right? And the thing is OSHA they finalize their current Selica standard in March of 2016, you know, after years and years and years of Rubikin. This is why the OSHA Selica, this is why OSHA OSHA standards take a long time to change the federal road making process is extremely long literally takes years sometimes decades, right? So it replaced an order standard that had been on the book since like 1971, right? So the the OPL, you know, it was based on some really outdated formula, you know, that Permitted exposures that these days were like, wait, why did we do that back in the day, right? They're like clearly harmful. So the new rule Lord the P.L. significantly, right? And added, you know medical surveillance exposure control planning hazard communication requirements that we're not there before, right? So compliance deadlines the we're June 2017 for construction and June 2018 for general industry and the maritime, right? And there are two separate standards you need to know, right? So there's general industry That's 29 cotofedra relations 1910.10 53 and then construction is 29 cotofedra regulations 1926.11 53, right? Maritime actually falls under the general industry standards, right?

So for the boards, you need to know both standards, you know, because they share the same exposure limits medical Medical surveillance requirements, but Construction though they have a kind of a unique compliance pathway. We call that table one. I'm going to talk about table one in a bit, right? So let's talk about the P.L. and the action level. You know that these are the let's get to the numbers, right? These are the highest yield values on the board exam, right? You need to commit them to memory right now, right? So what's the OSHA P.L. for respirable crystalline silica? It's 50 micrograms per cubic meter, right? Measure does an eight hour time weighted average, right? The action level is half of that 25 micrograms per cubic meter. And again, these values, they apply to the respirable fraction, right? So basically particles that are small enough to get into your view line, right? Generally, they tend to be like less than 10 microns in aerodynamic diameter, right? So again, just to summarize, 50 micrograms per meter cubed is the OSHA P.L. Right? If you exceed the OSHA P.L, you need to institute engineering controls. It's required. If the action level is 25 micrograms per meter cube, right? So if you go above this level, it's going to trigger monitoring and medical surveillance. And then remember, the NIOSH R.E.L. actually for crystalline silica is 50 micrograms per meter cube as well. It's identical to the OSHA P.L. Right? And then the ACGI H.D.

American Council of Government in industrial hygiene is, right? So they're TLV for silica is actually 25 micrograms per meter cube, right? That much is the OSHA action level, not the OSHA P.L. Remember, the OSHA P.L. is 50. So there is a board trap here that I think is kind of worth flagging, right? So the ACGI TLV for respirables crystalline silica is 25, right? That's the same number as OSHA action level, right? Again, I'm repeating this just to kind of get this in your brains, right? It's not the OSHA P.L. Right? So question, they may give you exposure data and ask, hey, which threshold has been crossed? Right? We may ask you to compare the OSHA and the ACGI H.D. Right? Again, know the organization that matches which number. Right? So again, remember, the action level it triggers specific obligations, right? Even when the P.L. has not been exceeded, right? So specifically, right? Once you're exposed to at or above the action level for 30 or more days per year, the employer must initiate exposure monitoring, medical surveillance, and all those things, which I'll talk about later, right? But at or above the P.L. of 50 micrograms per cubic meter, you need to institute engineering and administrative controls, right? They become mandatory, right? And you must have a written, this is very important. You must have a written exposure control plan. It must be in place, right? Now, if engineering controls cannot reduce exposure below the P.L.

Then respiratory protection is then required as, you know, kind of supplemental protection. So let's talk about this infamous table one that I talked about, you know, earlier, like, like, what's table? Like, what in the world is table one, right? So this is something that just applies to the construction standard, right? So it's a feature that actually doesn't exist for general industry, but it is more testable table one. So waste table one table one is pretty much like a list of like 18 specific construction tasks, right? You know, like handheld power sores, jackhammers, handheld grinders, talkpoint grinders, cord drilling, right? You know, along with engineering controls for each of these tasks, right? So it's like you have a specific task and then the engineering control required for that specific task, you know, depending on, you know, like, what does suppression methods, local exhaust ventilation, or both, right? Now, the thing is when an employer uses the equipment specified in table one, right? And it implements the controls that correspond to that piece of equipment. They actually presumed to being compliance with the PEL, right? So one critical thing to know here is that if you're doing these things, then no M-onitrain is required. Again, if you're following table one correctly, right? This is something called objective data compliance, objective data compliance.

But if the employer does not use table one, or if table one doesn't cover the specific task that, you know, that it's been performed at that job, then you need to do full M-onitrain, right? Just as in general industry, right? Just as in general industry, okay? And the monitoring, you know, results then dictate what additional controls are needed as a discripre. So again, again, remember table one, it's only available under the construction standard, not for general industry. Kind of deals with about 18 specific tasks, right? Specifies, you know, again, water suppression, local exhaust ventilation, right? And again, if you comply with table one, it eliminated the requirement for M-onitrain, right? And if table one is not followed, you need to do M-onitrain, right? And the employer must also provide respirators during table one tasks, right? If that task specifies that, hey, that's one of the things you should do. All right, so now let's talk about exposure assessment in general industries. So talk about construction. Let's talk about exposure assessment in general industry. So in general industry, the employer has to conduct initial exposure assessments for literally all workers who may be exposed to silica, right? So an initial exposure assessment has to be done for people that may be exposed to silica, right? You can do this by, you know, measuring the air monitoring, the person's personal breathing zone, right? Or you can do a through objective data.

So you know, like published data, you know, this published data on these things, right? Or historical monitoring results or, you know, industry characterization studies, you know, that show exposures below the action level, right? So the thing is if the initial results from your initial monitoring comes back below the action level of 25 micrograms per cubic meter, then you can stop monitoring there. You don't have to do any periodic monitoring after that. Unless, unless the job conditions change. But if the result is at or above the action level, but below the PEL, then you need to repeat monitoring every six months, every six months. So above action level below PEL, every six months. But if the result is at or above the PEL of 50 micrograms per cubic meter, then you need to repeat monitoring every what three months, right? So remember, this is that initial monitoring, right? Now, in all cases, you need to notify your workers. In all of these cases, you need to notify your workers of the exposure results within 15 working days of you getting those results, right? So again, remember, the monitoring frequency below action level, no periodic monitoring is required. Out of above the actual level will be low the PEL, right? So 25 to 50, right? Every six months, out of above the PEL, right? So 50 or greater every three months, and you need to notify your workers of the results within 15 working days, right? So now, let's talk about the medical surveillance requirements, right?

So if you go on the medical surveillance, right? Like what is involved there, right? And again, I think this is one of the most commonly tested things on the boards. Like what triggers medical surveillance, right? So the trigger is going to be an employee who is or will be, right? You know, occupational exposed to respiratory crystalline silica, out of above the action level, again, 25 micrograms per meter cube for 30 or more days per year, right? Guys, this 30-day threshold is extremely important, right? It is a calendar year count of days, right? So not like a cumulative hours calculation. So if you do do a silica generating work on 30 separate days in a year, even if each day is only part time exposure, you meet the threshold, right? You meet the threshold as long as you get in your 30 days, right? So what is that? What does that initial exam consist of? Well, it consists of it must be completed within 30 days of initial assignment, right? Or if it's a worker that has already been employed within 30 days of the dates, the, you know, standard became applicable to that employer, right? You need to start doing medical examination. You need to do the medical surveillance, right? So what does this include? Well, it includes a medical and work history, right? And we're going to emphasize, you know, respiratory symptoms, spread those exposures, tuberculosis, right? Another relevant comorbidities, right?

And then we need to do a physical, we're going to focus on the respiratory system, right? We're going to do spirometry, right? Specifically FVV1, FVC, right? You know, we want to establish some baseline long function. And then I'm going to do a chest radiograph. And that has to be interpreted by a NIOSH certified beer reader using the ILO classification system, right? And then on the initial exam, you need to do a tuberculine skin test or an interferon gamma release assay, right? Tuploculin skin test or interferon gamma release assay, you're going to see why as we're considering this podcast, right? And then after the initial exam, you need to do periodic exams every three years. They're required every three years, right? Not annually, right? This is a common wrong answer on board questions with CELICA. You do every three years, right? And the exam components, they remain the same, you know, history, physical, spirometry, you know, chest extra beer reader interpretation, right? So you got to keep those in mind, right? And remember, again, TB, you need to check, or check for TB, right? Especially on that initial exam TB, checking is really, really important, right? So now the thing is, if the person is being reassigned or terminated from their job, the employer must offer them an exam, you know, when the workers being reassigned away from a CELICA exposed work, right? Or they are being terminated from their employment, right? They need to do like a termination exam, right?

But this is only required if they've not had a compliant exam within the past three years, right? Within the past three years, right? So now let's talk about this B-RIT system and, you know, the ILO classification system. I'm not going to go into depth on this. It's not tested in a ton of detail, but you need to know some of it, right? Some of it is ILO, right? So remember the ILO classification of radiographs, right? Is the system that is used to standardize, honestly, the reading of chest x-rays for dust-related long disease, right? NIRS certified B-RIT is basically a physician that has passed a qualifying exam, you know, there's an exam you have to take, you know, that demonstrates proficiency in this classification system. So it pretty much classifies small capacities by shape and profusion. Shape and profusion, right? So the shape is going to be described as, you know, rounded, you know, and they use the letters like P, Q, and R for increasing sizes, right? Or you can also describe them as irregular and we use the letters ST and U, right? So rounded, P, Q, R, irregular, STU. And then profusion is kind of graded on a 12 point scale from, you know, zero slash zero meaning no capacities to three slash plus, which is like the highest profusion, right? Large repassities, you know, they're classified as category AB or C based on their cumulative size, right?

Again, you don't need to know a ton about this, but just make sure you know the word shape, know the words profusion and things like that. Right? So for silicosis specifically, the classic pattern on chest radiography, right, is operalo predominant, you know, small rounded opassities, right? And then you may see excel calcifications of the hyalur lymph nodes, right? So excel calcifications, when you see it on a board question, it's pathonomonic for silicosis, all those requisite doses can also cause that, but think silicosis, right? So in the context of occupational exposure, think of silicosis, right? And then after you do the medical exam, right? The healthcare provider sends a written opinion to the employer, right? Well, this is a critical confidentiality point you need to know for your test, right? The written opinion, it may only include the following, it may only include the following, right? So confirmation that the exam was performed, any limitations on the workers exposure to silica and a statement on, hey, you're going to need for low PS or no, right? The provider cannot include specific findings or diagnoses or clinical details to the employer without the workers' written consent. The worker doesn't give you a written consent, can do it, right? So again, this mirrors the confidentiality framework that you see across many of the OSHA medical surveillance standards. So now, let's kind of talk about, you know, some clinical stuff with silica, right?

So what are the three forms of silicosis, right? There are three clinical forms and the thing is the boards they expect you to know all three, right? You need to be able to distinguish them by exposure type, latency, radiographic, clinical features, right? So let's kind of go through those, right? So chronic silicosis is the most common, right? And you know, it's the classic one, right? You get it from low level prolonged exposure, latency is typically more than 10 years, right? And the key features, you're going to see, you know, upper-low lobe nodules, you know, excel, higher calcification of your lymph nodes, right? And you may progress after you, after you've been removed from silica exposure. And then the second big type of clinical silicosis is the accelerated form, right? You typically get this from moderate to high level exposure, latency is like five to 10 years, right? And you're in this, in these people, you're going to have like just rapid progression of the nodules, upper-low predominant disease, right? And these people, unfortunately, they have a high risk of something known as PMF progressive-massive fibrosis, right? And then the third distinct clinical silica picture you should know for your test is acute silica exposure. Sometimes they call this silica proteinosis, right? So this usually happens when you have like very high intensity exposure. The latency is like weeks to five years, right?

You're going to see ground glass opacities, you know, crazy paving pattern on a CT. Keep that buzz already in mind, crazy paving pattern on a CT, right? And it's rapidly fatal, right? And you know, if you, you know, the stuff that feels obvious, oil is going to be PES, it's going to be PES positive, right? Purely casage shift positive, right? This is rapidly fatal, right? So again, don't forget chronic silicaosis, most common form, you know, years after low level exposure, again, pattern of money finding, bilateral operolube nodules, right? Highly lymph nodes, you're going to see peripheral calcium deposits, right? It kind of looks like a ring. That's where the term x-hell calcification comes from, right? So you see a board question that shows operolube nodular pattern with x-hell hyalur, you know, calcification like in a coal miner or sand blaster or stone quarter, that silicaosis until proven otherwise, right? Now acute silicaosis, right? You know, again, like the worst one, right? Silica proteinosis is the most severe, right? So basically, the results from just overwomen exposure over a very short time frame, right? Radiographically, it actually looks like something called a pomenarevula proteinosis, right? You're going to see bilateral grand glass opacities. I'm going to see again, the crazy paving pattern. Look this up, the crazy paving pattern on CT, right?

So histologically, your vial are going to be filled with again, PES positive, you know, proteinitious material, right? Progress is rapidly respiratory failure, right? Fiddle within once to a few years, right? It's really bad, it's really bad, right? Now, I just want to maybe comment on this thing called PMF, progressive massify process, right? PMF, PMF, PMF, right? Basically, this happens when silicaotic nodules, they kind of come together into like large opacities, right? So the ILO, they define PMF as opacities greater than one centimeter in diameter, right? These are large opacities, large opacities, right? You know, large opacities, right? You know, they're going to be graded as AB or C on the ILO scale, right? A is like less than five centimeters combined, B is, you know, larger opacities and then C is like, wow, this thing occupies more than one third of the long field, right? That's obviously like super bad, right? Now PMF, you know, people that have PMF, their FV1 is going to start tanking very, very quickly, right? And it's actually the leading cause of death in silicaosis. This is high yield. The leading cause of death in silicaosis is progressive massify process, right? Now, one thing I've noticed that the boards love to test with silicaosis is that they love to test some systemic and associated conditions with silicaosis, right? So what are the clinicals, SQLI of silica exposure, right?

What are these clinical SQLI that, you know, are beyond the classic silicaosis of the lungs that the boards love to test? Well, let's talk about these associations, right? The first one is lung cancer, right? In fact, IARC classifies crystalline silica as a group one carcinogen, right? Group one carcinogen in the context of silicaosis, right? Again, the mechanism is not fully understood, but we know that silica causes chronic inflammation of the lungs, regenerative oxygen species, it impairs the any repair, right? So again, board questions they do require you to know the IR classification is class one, right? Now, what's the next association with silicaosis? Think of TB, TB, TB, TB, TB, right? Silica, and what's the mechanism here? This is something we do understand. Right? Silica, it's toxic to alveolar macrophages, right? And the thing is, you have alveolar macrophages, they're super important, right? They're like the primary immune defense against Michael Bachterm tuberculosis, right? So you have a worker of silicaosis, you know, they have an approximately like three-fold increased threshold risk of developing active TB compared to the general population, right? So this is the biological rationale behind like us doing like TB testing in the medical surveillance protocol, right? So the boards may give you a scenario of a sun blaster or minor with a new pulmonary infiltrate and expect you to basically say that hey, this person's got TB, right?

Now, what's another thing associated with silicaosis? Think of autoimmune disease, right? Silica exposures are pseudo-scleroderma, right? You know, sometimes we call that systemic sclerosis, right? Also, silica exposures are pseudo-romatoid arthritis and lupus, right? So lupus, R-A, and scleroderma, right? The scleroderma link, I'll see, is probably the one that is the most well-established, most commonly-bored tested, right? You know, Kaplan syndrome, you know, Kaplan syndrome where you have like chromatoid arthritis, you know, with large pulmonary nodules in a pneumoconylosis patient, right? It can also occur with silicaosis, right? So many people think that Kaplan syndrome only occurs in co-workers. No, no, no, no, it can also occur with silicaosis, right? It can also occur with silicaosis, right? So, classically, it's describing co-workers, but it can absolutely occur in silicaosis as well. That's something definitely want to make sure you know for your exams, right? And then another silica association is renal disease, right? So silica exposure can lead to development of glomerulone arthritis, right? Probably through some immune-mediated mechanism or whatever, right? They don't test this as commonly, but you should just kind of slow that into your brain for your exams, right? And then COPD, right? Silica can also cause obstructive lung disease, independent of tobacco use, right?

So you have workers with high exposures, they may actually develop air full obstruction, believe it or not, even if they don't have visible nodular disease on a chest x-ray. Now, let's talk about high risk industries, right? Because again, many times on these board exams, they will give you like some industry and then based on the industry or the, you know, task that is described, you need to figure out like, hey, this is the potential exposure, right? So occupations that are high risk for silica exposure, right? It's going to be things like some blasting, abrasive blasting, construction workers that are pretty like jackhammers, you know, grinders, you know, people that use salts on concrete or misery, you know, tunnel workers, that's a high you don't want to know, right? Foundry workers, miners, people that do pottery, ceramics, right? Glass manufacturers, right? And then a big, big, big one, it's like an emerging topic on the exam, right? Or people that fabricate countertops, people that fabricate countertops, right? The, the, the engineered stone countertop industry is like a special one you should definitely know for your exams, right? Because it's an emerging problem, right? It's an emerging problem, it's an emerging problem, appears on board exams, right? So the thing is engineered stone, you know, we call that, you know, like quartz, quartz, you know, artificial stone, right?

Is manufactured from literally like 90 to 95 percent, man, 90 to 95 percent crystalline silica, right? So when fabricators caught grind polish these slabs, they are generating extremely high concentrations of respirable silica, right? So this is a big problem, right? And we're seeing, you know, many cases of rapidly progressive phyto silicaoses in young workers in the US, in Israel, in Australia, in Spain, you're seeing licenses of only like two to five years, right? So this is kind of a big problem, right? So these workers, they developed, you know, accelerator or acute silicaoses at ages well under age 40. So you're like, hmm, what's going on here, right? So, so the thing is, mayors, they've actually issued a lot of like hazard alerts, and OSHA has been doing a lot of enforcement in this, in this sector, right? So if a board question describes a young countertop fabricator with rapidly progressive young, long disease and a short occupational history, think of engineered stone silicaoses, engineered stone silicaoses, right? Now, let's talk about hazard communication with silica, right? So the thing is the OSHA silica standard actually requires employers to provide training to all workers that are exposed at or above the action level, right? Now this training must cover things like the health hazards of silica, which operations generate exposure, right? What are the specific controls in place? What's the purpose of medical surveillance, right?

And how do you use and maintain the required respiratory readers, right? And you must have a, you must also have a routine exposure control plan. It's actually required, it must be at the work site, right? It must describe, hey, what are the regulated areas? What are the regulated operations? What are the engineering controls? What are the work practices? What's the respiratory protection you use, right? What are the housekeeping measures that are employed, right? In construction, if you're using table one, that famous table one I talked about, right? The routine plan is going to document the tasks and it's going to map them to the table one controls, right? So again, regulated areas, you need to establish them, you know, when the exposure is exceed the PEL, right? So again, these regulated areas, right? The access is kind of restricted. It's going to be restricted to authorized workers, authorized supervisors, right? Eating, drinking, using tobacco in these regulated areas, not acceptable, not acceptable, right? So don't forget about hazard communication, training and this reading exposure control plan with Silica. Now let's talk about respiratory protection with Silica, right? So respiratory protection, right, is the last line of defense, is the last line of defense after engineering and administrative controls, right? So the standard follows the hierarchy of controls, right?

So again, elimination first, then substitution, then engineering controls, then administrative controls, then respiratory protection, right? Respirators are never a substitute for good engineering controls, right? So when respirators are required, right? The selection is based on the airborne concentration of Silica, you know, relative to the PEL, right? And the APF, you know, the assigned protection factor, right? So if you have exposures that are up to 10 times the PEL, you need to use a half face air purifying respirator with a P100 particulate filter, right? You know, that provides like an APF of 10, right? APF of 10, APF of 10, right? So again, let's highlight this, right? Exposures up to 10 times the PEL, you need a half face air purifying respirator, right? With an APF of 10, you know, with a P100 particulate filter. Again, these specific details, those are the annoying things that our friends at the boards do want you to know, right? But if you have higher concentrations, then you need to use a full face, you need to use a full face respirator, right? With an APF of 50, right? Or you can use the PAPR, a purified air purifying respirator with an APF of 25,000, you know, depending on the type, right? Now, all the respirator use, you know, with Silica, remember, it has to comply with the OSHA respiratory protection standard, right? Remember, that's a 29-cord of facial regulations 1910.134, right? You know, it has to comply with that. It has to comply with with that.

You need to do like your feet testing, your training, and all that, all that stuff, right? So, what if they give you a question about like a 52-year-old man, you know, comes to your occupational medicine clinic for a surveillance exam, you know, he has, you know, worked as a Foundry Modemaker for 22 years, right? He's saying that, hey, you know, I have some exertion over the last two years, but, you know, he says that, you know, I'm getting older and I also smoke, right? You know, they tell you that he has like a 30-pack year tobacco history just with five years ago. And then you're told that's pyromatry, reveals like a mild restrictive pattern, you know, with an MVC that is 72% of predicted, if you want to, MVC of 0.82, right? And then they tell you that a chest X ratio is bilateral upper low, small rounded opacity with a profusion of two, you know, two, you know, two-slash one on eye-alow classification, right? And then they tell you that, hey, high-level lymph nodes, they enlarge their peripheral classification, right? So, the X-hell classification is if you may, and then they ask which of the fullings the most appropriate next step in management, right? And they give you an answer that says, hey, we're actually on the patient that these pyromatry findings are fine, right? Or they give you an answer that says, hey, refer for CT guided long biopsidoconfertil from the diagnosis, or they say, hey, do an interferon gamma-release acid for TB, right?

Or they say, hey, statcoticosterotherapy for hypersensitivity demonitis, right? Or they say, you know what, refer to pulmonology for bronchoscopy with BL? What should you do here? Well, I would hope you're saying, okay, divine. I'm going to do option C, right? I'm going to do the third option, right? This is classic chronic silicosis in a foundry worker, right? So they have this operalo- predominant, you know, small rounded opacities, right? Iolo-provision of two-slash one, right? That's significant silicosis, right? And again, you see the X-hell calcifications, right? It's pathonomonic, right? So, you don't need to do a biopsidococcus, right? You have the occupational exposure history, you have the consistent radiographic pattern, right? The pyromatry again is showing a restrictive pattern, which is pretty characteristic of silicosis, right? So what's going to be your next step? Test for TB, right? Remember, silicosis increases your risk of TB by 3-4, your risk of active TB by 3-4, you know, because again of the microfiche dysfunction, right? So remember, the medical surveillance standards specifically mandates, hey, test for TB for this very reason, right? So you can do an interferon gamma-release-acere TB skin test, right? If it's positive, then you should recommend, you should offer treatment for lethal TB infection, right? Because again of the elevated risk of reactivation compared to the general population, right? So keep that in mind, all right?

So what if they give you a question about like some general contractor, you know, he has 35 employees and they do, you know, concrete cutting, they do demolition work, right? And then an industrial hygienist, you know, has, you're told in the question that you have some industrial hygienist, he's done like personal breathing zones sampling for, you know, respirable, you know, crystalline silica, right? And then there is also that, hey, it workers, they have an eight hour time-witted average exposure, ranging from 28 to 46 micrograms per meter cubed, right? There are many workers who are below 20 micrograms per meter cubed, right? And you're told that, hey, this employer currently has no medical surveillance programming, please. What should you do? Right? So in fact, let me put it this way. Let me give you a few statements and then what are the employer's obligations, right? Let's pick one from this, right? So option A, you know, they say, you know, hey, no, no, they tell you, because no workers exceeded the PEL or 50 micrograms per meter cubed, the engineering controls or medical surveillance is required. Option B, right? Hey, it workers with exposures are above 25 micrograms per meter cubed must be enroute in the medical surveillance program. If they work 30 or more days per year in silica exposed tasks, option C, all 35 workers must be enroute in medical surveillance, because silica work is being performed at the site.

Option D, medical surveillance is only required if a worker develops symptoms of silicaosis. Option E, the employer can just defer medical surveillance until a repeat sample confirms and the video exposures. What should you do here? I would hope you're picking option B, pick an option B, right? So this question basically is testing the action level trigger, right, for medical surveillance, right? So remember, under both the general industrial and construction silica standards, medical surveillance is required for any employee who is or will be, who is or will be exposed at or above the action level of 25 micrograms per meter cubed for 30 or more days per year, right? It of the workers have exposures between 20 and 46, right? So they are above the action level, right? If they perform the work on 30 or more days annually, medical surveillance is mandatory regardless of whether they exceed the PEL or not, right? And then answer A is wrong, right? Because exceeding the action level, not just the PEL is what triggers these obligations, right? C is wrong because, you know, the threshold is the action level exposure, not simply just being on a silica work site, right? The trigger is being above the action level, right? Answer D is wrong because medical surveillance is a preventive program, right? Is a preventive program, is not a response to symptoms, right? And then option E is wrong, right?

Because the sampling results already confirm that the action level is exceeded in eight workers, right? So you need to do medical surveillance for the eight workers, right? Now, what if they give you a question about like a 34 year old man, you know, he's referred to your clinic, you know, he has a six month history of progressive dysmiac cough, 10 pound weight loss, right? And you're told that he immigrated from Central America four years ago. And since he arrived in the US, he's been working as a stone fabricator at a countertop manufacturing facility, right? And then you're told he does not smoke and chest City shows, you know, bilateral period hyalur, ground glass opacities, crazy paving pattern, no discrete nodules, right? And then you're told that PF Ts reveal like severe restrictive defect, you know, markedly reduce DLC, right? And then they tell you that, hey, you do a bronchial viola lavage and you see PES positive, you know, lipoproteinitions material and the cell LDH is markedly elevated, any antibody, anti-GBM antibodies are negative, right? What's going to be the most likely diagnosis, right? Option A, high percentage activity in the immunitis from occupational antigen exposure option B. Pomenariavular proteinosis secondary to silica exposure option C, sarcoidosis, option D, chronic silicosis, option E, good posture syndrome, right? I really hope you're saying that divine, this is going to be answer B, right?

So this vignette is pretty much describing acute silicosis, right? You know, sometimes it's called silica proteinosis, right? Young countertop fabricator, right? So remember, engineered stone, engineered stone slabs, as I said, right? Very high crystalline silica content, right? Like literally like 92, 95 percent, right? And fabrication generates very high respirable silica concentrations, right? So the short latency, you know, this person has just been working for like four years, you know, combined with the alveolar fill-in pattern on CT, the crazy PV and appearance, right? PES positive material on bronchial viola lavage, right? severe restrictive defect, that tells us that weight. This is acute silicosis, right? Remember, you know, the other answer, circle E doses is going to show lymphatic, granulomas, different clinical course, right? Not this, you know, like crazy rapid, and it's not going to show like the crazy PV and whatever, right? High percentage activity in the United, right? It's going to be a person that typically is working with like organic antigens, you know, like they're working a barn or something like that, right? Chronic silicaosis is going to show like discreet upper loop nodules, right? Not an alveolar fill-in pattern. Good posture syndrome is, you know, involves anti-globarolabies, membrane antibodies, right? And you'll have him up to this, right? So again, don't forget, engineered stone exposure, connecting, connected to acute silicosis, right?

And again, know that the pathology mirrors something called a pulmonary alveolar proteinosis, right? So again, let's just do a quick summary to kind of wrap this up, quick summary to wrap this up, right? So again, remember, the PL is, so if you're like, oh, divine, what are 10 things I gotta know about silica before my exams? Let's, they, they, they, they, they gotta lock this in your brain, right? So PL 50 micrograms per meter cubed, right? It's our time-related average, you know, the action level is 25 micrograms per meter cubed, right? So it's half that, right? The ECGH TLV, right? It's 25 micrograms per meter cubed. So this is the second thing you want to know. ECGH TLV, 25 micrograms per meter cubed, the mach is the ocean action level, not the PL, right? Number three, remember the construction standard and table one. If you comply with table one, you don't need air right? Number four, remember medical surveillance is triggered if you're at or above the action level for 30 plus these are year, right? Number five, the periodic exams are going to be every three years, not annually, right? And includes pyromatry, chest x-ray that should be read by a B-reader right on a TB test, right? And then number six, remember the employee rating opinion, it should not include the diagnosis or specific clinical findings. Number seven, know your forms of silicosis, right?

The chronic one that's more than 10 years, the accelerated one that has a latency of five to 10 years, and then the acute form that is weeks to five years, right? And then number seven, right? Remember acute silicosis mimics pulmonary avial proteinosis, right? You're going to see PES positive avial feelings, right? Crazy PV pattern on CT, right? Number eight, remember, X-shell peripheral, so they may not use the term X, they may use peripheral higher calcifications, right? That's patholomonic, right? Remember, both have silicosis, they have a three-fold increase risk of TB, active TB, compared to the general population. And then number nine, remember, silica is an IRC group one carcinogen, right? And don't forget the very strong association with scleroderma. And then number 10, remember, engineered stone has 90 to 95 percent crystalline silica, right? Causes accellerated disease in young workers, right? So I think I'm going to go ahead and stop here. Again, hopefully you find this podcast to be helpful. Well, these things are pretty high yield to know for your test, right? So, you know, God willing, you know, next week or thereabouts, I'll make another podcast on something that is op-med boards relevant. So thank you for listening to me today. I will see you next time. Have a wonderful week. God bless you and bye for now. All right. Thank you.

The PEL is $50 \mu g/m^3$ (8-hour TWA). The Action Level (AL) is half of that, at $25 \mu g/m^3$.

The ACGI TLV for respirable crystalline silica is $25 \mu g/m^3$, which is identical to the OSHA Action Level (AL), but not the PEL.

Exposure at or above the Action Level ($25 \mu g/m^3$) for 30 or more days within a calendar year.

Every three years, not annually. This is a common board trap.

The presence of X-shell calcifications around the hilar lymph nodes.

Fabrication of engineered stone countertops (quartz).

Silica is toxic to alveolar macrophages, impairing the immune defense against Mycobacterium tuberculosis.

Chronic (>10 years); Accelerated (5–10 years); Acute/Proteinosis (weeks to 5 years).

Chronic shows upper-lobe nodules and X-shell calcifications; Acute shows ground-glass opacities and a "crazy paving" pattern.

Full air monitoring is not required, as compliance with the specific controls listed in Table One provides objective data of compliance.

Systemic Sclerosis (Scleroderma), Rheumatoid Arthritis (RA), and Lupus.

Silica is toxic to alveolar macrophages, impairing the immune defense against Mycobacterium tuberculosis.

Chronic (>10 years); Accelerated (5–10 years); Acute/Proteinosis (weeks to 5 years).

Chronic shows upper-lobe nodules and X-shell calcifications; Acute shows ground-glass opacities and a "crazy paving" pattern.

Full air monitoring is not required, as compliance with the specific controls listed in Table One provides objective data of compliance.

Systemic Sclerosis (Scleroderma), Rheumatoid Arthritis (RA), and Lupus.