This last set of slides completes the loop between health effects, workplace exposures, and surveillance examinations and covers OSHA medical standards and the surveillance requirements under those standards. Surveillance standards usually have some features in common. They usually specify which workers come under the requirements of the standard, some type of level that has to be measured and at which surveillance kicks in or is instituted, how often and how frequently the exams are done, who is responsible for performing them, sometimes the contents of exams, even to laboratory testing, and what happens afterwards, how the workplace and the worker are to be notified. Medicine is an ever-changing science. The OSHA standards, however, are not, and they have to be altered and go through a very time-consuming process if they're going to be altered. So, for the most part, they don't specify any medical actions or treatment that you need to take. It doesn't tell you necessarily what action to take in the event that you diagnose overexposure or disease. Lead is an exception because of medical removal protection within the standard, and it doesn't specify what medical treatment needs to be taken with positive findings in a specific worker. Some information moving on from a prior slide. OSHA often defines who falls under the requirements of a specific standard. In some cases, these are specified via measurement, such as noise, where it's exposure to 85 decibels in 8-hour time-weighted average, and for lead, where there are airborne measurements. A little more loosely, those workers who come under the blood-borne pathogen standard are those who are reasonably expected, based on their job, to have exposure to blood or body fluids, and this needs to be defined by the company or organization. As well, a few examples of what's done after a surveillance exam. In many cases, they mandate worker notification of risk or disease, such as in the asbestos and blood-borne pathogen standard. If there are high levels of lead or cadmium, the standard may mandate medical removal, and as in the respiratory protection standard, it may mandate that an individual worker is certified to be fit-tested and therefore to wear a respirator. This slide is not to be memorized. It just indicates really how few substances really are under OSHA medical surveillance requirements. I've highlighted a couple of the major ones in yellow, and these are some areas we'll touch on, such as asbestos, lead, noise, the silica standard, because it's relatively new. And a brief list of some of the case examples we'll look at. Initially, the respiratory protection standard, because it's relatively universal across a lot of industries. The silica standard I mentioned because it's new, and we'll touch on lead, noise, asbestos, and a few other areas. This should technically be titled the OSHA Personal Protective Equipment Standard. However, it's really concerned with the use of respirators. It was promulgated in 1998, and it was really because of the reasoning that respirator wearing can be hazardous. It's not an entirely benign procedure for workers. And as you see in the top table, there can be fatalities. They're not many, but even one fatality is too many. And in the lower table, there's a summary of the fatality rates before and after the respiratory standard was instituted. And across each of the sectors in industry, you can see a drop in the fatality rate following the institution of the standard. One initial question is, what is a respirator, in fact? And interestingly enough, the OSHA Respiratory Protection Standard doesn't define that. So you have to work from two ends. You have to think about it in terms of design. And it really means it's an enclosure that's covering your breathing zone, the nose and the mouth, or more widely, the entire face and head, which also encompasses breathing zone. Or it could be defined by function, and its function is to either prevent inhalation of harmful airborne materials. Those can be particulates such as silica or asbestos. They can be gases or vapors. They could be biologicals like tuberculosis. Or they should be designed to provide a source of respirable air in an oxygen deficient atmosphere. This is mainly in SCBA. Some visual representations of respirators to get you acquainted with the different types. Over on the left is the N95 mask, familiar to most of you in the hospital and what we assumed would be TB protection for the most part here until the COVID-19 pandemic meant it became the mainstay for other protection against that disorder. In the middle is the particulate respirator. This is used, for example, for silica dust exposure. And the half-face air purifying respirator, which has a gas or vapor cartridge and absorbs gases or vapors onto the cartridges in place before they come into the breathing zone. On the previous slide, those all represented negative pressure respirators. In other words, respirators that were activated by inhaling. On the other side here, we see the positive pressure respirators. These have an air supply and the two on the left-hand side are powered air purifying respirators. These have a line coming in and cover either much of the face or fit on as a hood as in the picture on the left. These are attached to a powered air source, which oftentimes may have a HEPA or other type of filter prior to entraining oxygen through the line to the breathing zone. Over on the right-hand side is a self-contained breathing apparatus. This is used for air supply in an oxygen deficient atmosphere. And you can see the tank over on the left of that apparatus. What are the health hazards of respirator use? We tend to think in terms mainly of cardiopulmonary disorders, individuals who have asthma or restrictive lung disease, or whose cardiac condition may not permit the use of a respirator, or they may increase the metabolic workload. There's some other useful points here, however. They can decrease sensory output quite a bit, and this will increase the risk of accidents. If you can't communicate with co-workers or see warning lights or hear warning bells, that may increase that risk. And asphyxiation can occur in the case of online respirators from improper air sources. The physiologic effects tend to be cardiopulmonary. They can increase dead space, and the negative pressure respirators, as you can see by the way they work, will increase airway resistance. This oftentimes is not a problem in the young and healthy worker, but in someone who has extant lung disease, that may become something of a tipping point for them being able to work. That increased work of breathing and increased metabolic workload can increase cardiac workload, as well as the weight of the respirator, particularly in the case of SCBAs. Other of the important physiologic effects is the effect on body temperature. The air-purifying respirator will decrease heat loss from breathing. If you think back a couple of slides in the PAPR with the guy who was wearing a big hood on, you can imagine that heat loss may build up within that hood fairly readily. Some of the other air supply respirators, the heat gain or loss is going to depend on the temperature of the supplied air, so it may vary depending on the circumstances. One of the important problems with a respirator is the fact that impermeable clothing may often need to be worn for accidents, firefighting, and other types of work. The combination of a respirator with that protective equipment, particularly if it's impermeable, may really increase heat gain or retard heat loss and cause that increase in body temperature as a result. A few other effects that may be less well considered. Some people may have allergies or bad reactions to the respirator mask. It could be made of rubber material that can sweat underneath it, and so that may aggravate folliculitis or produce acne across the face of someone who's particularly sensitive. People may get claustrophobic within the masks, and that's worthwhile considering because if they have to wear it for emergency response, they may not be well-functioning as a result. People like to chew tobacco or smoke, and that leads to loss of habits that they find soothing or helpful to them. And in pregnancy, there can be changes, particularly in the second half of pregnancy, with the gravid uterus pushing up against the diaphragm. FVC will diminish. Tidal volume might diminish. Maximum voluntary ventilation or hyperventilation might start to occur, and that can also be aggravated by a respirator. Although we tend to focus on the medical evaluation of workers for fitness to wear because that's the doctor's role, the OSHA Respiratory Protection Standard has a number of other subparts. It mandates procedures by which the workplace needs to select respirators. They need to identify the hazards. They need to identify user factors and the best protective means of choice for a respirator. After medical evaluation, there needs to be fit testing. Subsequently, there needs to be maintenance procedures. How do you clean it, disinfect it, storage, repair, or discard it? And there needs to be worker training, and that has to occur annually. So moving on from the previous slide, the workplace has to consider a number of factors in the selection of respirators. What's in the atmosphere? Is it oxygen deficient? In that case, you need an air-supplied respirator, such as an SCBA. What are the contaminants? You're going to need a very different mask or respirator for particulates than you will for gases and possibly for biologicals. How toxic is it? What are the possibilities if there is an exposure? What areas should be exposed? Do you need eye protection, particularly if you're working with irritant gases or vapors? Then a full-face respirator with eye protection is going to be needed. And the workplace has to think about how long they can expect workers to wear respirators because they are uncomfortable and workers will want to get out of them at some point. The medical qualification to use a respirator must be done prior to respirator fitting and fit testing and done prior to when the worker is expected to use a respirator. There are a couple of options. People can come in for medical examinations in the past, but one of the novelties of the OSHA respirator standard was that it allowed doctors, physicians, and health care providers to use an initial screening questionnaire and then follow up by medical evaluation in a few select cases. In other words, only the individual workers who needed to be further tested need to come in or be seen after the questionnaire has been completed. So, in using the questionnaire, it's mandatory that every worker complete one. It's mandatory that the employer send them out to make them available to the workers. These then need to be completed by the workers and sent in in confidence. It's oftentimes a good idea to have them sent directly to the physician or the physician's office rather than to the employer or allowing the employer to collect them. If there are positive responses to the mandatory questions, then further evaluation of that worker is required, but that can be determined by the licensed health care practitioner. And it could consist of a telephone conversation. And as many of you who have experience with doing this, most of these can be adequately screened and answered via phone conversation if they do put down positive answers. And so, just to enlarge on the previous slide is that the content of any further evaluation beyond the questionnaire by the health care professional is not specified and not mandated. And it could, as I said, just be a phone interview. There are no specific tests that are required, so the standard doesn't require if you answer yes to X, Y, or Z, you need to obtain pulmonary function testing. Or if you answer this to Q, X, and R, you need a chest X-ray. So, it's completely dependent upon the judgment and the evaluation by a health care practitioner. One useful point to outline is that workers may need respirators, but they also may need to be examined under other OSHA standards such as the asbestos standard for which they will need a respirator. The OSHA asbestos standard, for example, requires spirometry annually and it requires X-rays at specified intervals depending on age and time of work. So, those requirements for testing such as spirometry are not superseded by the respirator standard. In other words, if the worker handles asbestos, they come under the asbestos standard, they need a spirometry, even if they have a nice clean questionnaire with no positive answers under the respirator standard. The OSHA standard also does not specify when respirator use should be restricted, and it leaves the practitioner with a lot of discretion with respect to restricting or forbidding respirator use because of health problems. There was an old prior ANSI standard that suggested restriction if FEC was below 80% or FEB1 was below 70%. And as you look at those, those are probably far too restrictive. You probably have patients or workers who are below those indices who wear a respirator just fine. So, those recommendations were considered too restrictive, and fundamentally, there's no way to write rules in concrete for restricting respirator use. There's some fairly clear-cut cases where you should consider limiting a respirator or restricting it. If people have severe cardiopulmonary disorders, ischemic heart disease, severe hypertension, and arrhythmias, depending, again, upon the type of respirator, these are people who may present a hazard to themselves if they're going to be wearing a respirator, particularly if it increases their work, or it limits them in some other way at work. So, it's not exactly a no-brainer, but it's pretty close. By the same token, people with very severe obstructive lung disease, particularly COPD rather than asthma, which would be reversible, or if they have severe restrictive disease, and again, respirator is going to increase the work of breathing, you should consider limiting or restricting them from wearing a respirator. Probably the most important question to ask them at the start when you talk to them is ask them whether or not they've been able to wear a respirator before, and if they say yes, they have, or they have been wearing one recently, then that's about as good guidance as you can get. If, by contrast, they have some other demonstrable inability to wear a respirator, then you would want to dig and find out what that might mean, because that might mean you have to restrict them in some way, shape, or form to using it. If anything interferes with a good facial seal of the mask to the face, you have to consider what type of respirator they can wear or whether they can't. People have to trim their beards. There's always the passive-aggressive worker who trims the beard and exactly the outline of the respirator so they keep the beard and it fits along it. But if they have facial scars or deformities, that may interfere with a good seal on the mask too. As well, some individuals might have neuromuscular disease. They may be older or have bad arthritis or immunologic-rheumatologic disorder, and if they're unable to use or care for the respirator or, importantly, to don the respirator or doff it, then that's going to really affect whether or not they can wear it, and so you may consider restrictions for those people too. This is a quote which I won't read in PowerPoint karaoke style, but it really suggests that limited qualifications and re-evaluating the very small number of workers with specific health problems is probably useful, and if you can follow those along or identify people who have really bad cardiovascular or pulmonary disease and restrict them, that's probably the best way to go. Another way I like to look at this is to consider what the potential bad outcomes would be and whether or not they can be mitigated. So, for example, if you're talking about an N95 respirator that's used to go in and see patients with active tuberculosis, if you're assigning a resident to wear one of those and they have bad asthma, the consequences of developing a bad asthma episode while wearing the respirator is going to be significant. If, however, you have the same bad asthmatic and they may be operating in a confined space, for example, then assignment of that person to wear a respirator where they may need someone else's assistance or may not be able to fully extricate themselves safely is going to lead to more severe consequences, probably for that person and possibly for co-workers. So in that case, because of the circumstances of the respirator wearing and use, you may not want to restrict, you may not want to assign that person, you may want to restrict that person from wearing a respirator, whereas, for example, the hospital resident with bad asthma in an N95 may not need to be. There is no mandate under the OSHA respirator standard for re-evaluation, in other words, filling out a questionnaire every year and being evaluated for it. However, the standard does require annual training and probably, in most cases, annual fitting and fit testing. So what do you do about this? Do you just give them a medical evaluation once and be done with it? Probably not the best idea, but on the other hand, giving a large group of people a questionnaire over and over again isn't particularly efficient or helpful for either you or the workers. So some reasonable approaches to re-evaluation have been suggested. You could give a periodic questionnaire every couple of years. In the main, however, you should probably let the workers in the workplace know that as soon as a worker is having difficulty or a problem with a respirator is encountered, they should notify the workplace and notify you so you can re-evaluate that. If there's a change in workplace conditions, new materials have brought in, a new process has been brought in, or increased workload is happening at the workplace, that may require different thoughts about who can wear a respirator and who might not be able to. And if there's new medical information in an individual worker, you should be notified if someone is developing pulmonary disease, is developing cardiovascular disease, and angina. Obviously, you want to know about it because that's going to change your assessment of who can wear a respirator. ANSI and some other organizations have suggested age-based recertification, in other words, doing it every five years for young workers and annually or biannually if they're over about 45. And so those are all reasonable approaches to it, although they're not written into the standard as a standard doesn't have a requirement for annual or periodic re-evaluation. We're going to lead off with the silica standard, partly because it's a relatively new standard and many may not be as familiar with its implementation as some of the older standards, partly because there's a lot of workers affected, over 2 million workers in the U.S., and so the potential for silicosis still remains, partly in old industries including construction, mining, quarrying, sandblasting, the things you normally think of when you think of silica use. And then there's a lot of new industries, for example, stone manufacture. There's manufacture of artificial quartz and artificial stone countertops, and then of course there's cutting of artificial and natural stone countertops, granite, quartz, and marble, and many workers are exposed to silica dust in small shops with poor controls, and there have been a number of reports fairly recently about silicosis in this group. Hydraulic fracking uses silica to open up the pores that have been blasted down the pipe to enable gas to escape from the shale, and in recent decades there's been an increase in coal mining with also concomitant silica exposure, so a lot of old and new industries together representing those exposed to silica. So just to give you some numbers on silica exposure and the reason for the change in the standard, OSHA's prior PELs for crystalline silica were 100 mics per cubic meter in general industry, and in construction in the shipyards it was much higher, up at about 250 micrograms. The reason for the change was that there was a fairly good base of epidemiologic studies that showed the risk for both silicosis and for lung cancer was demonstrable in workers who were exposed below 100 micrograms per cubic meter, so OSHA reduced the PEL in the current standard as of two years ago to 50 micrograms per cubic meter, and the action level is half of that at 25 mics per cubic meter, and at the action level those are individuals who have to wear respirators or otherwise come into the purview of monitoring for it. Now compliance is a little bit different under the OSHA silica standard than we're used to in other standards. For general industry you can go ahead and just measure air levels, so they require measurement of silica airborne levels and use of respirators if they come above the action level. For construction, because those workers are often working in small shops, different places day to day, no real fixed place of employment but a new building or a new streetscape every time, there's a couple of things they can do in that industry. They can use wet dust suppression methods or local exhaust ventilation or both, in other words adequate engineering controls for dust suppression, and that way the workers don't need to necessarily wear respirators and they don't have to be seen under the OSHA standard if the company is adequately protecting them with those engineering controls. Or, like general industry, they can measure the air levels and use respirators if there's levels measurable above the action level. So given the difference in controls, who's coming under the purview of the OSHA silica standard? In general industry, fairly simple again and straightforward, it's workers who are exposed at or above the action level, because it's been measured, for 30 days or more per year. In construction, it's workers who are required to wear a respirator for over 30 days per year. Remember that they can measure and put the workers in respirators, but they can also institute those engineering controls, wet dust suppression and or local exhaust ventilation, and if those things are going on and they can be demonstrably effective, then those workers don't necessarily need to have medical surveillance because the controls are adequate. And medical surveillance exams are done under the OSHA standard for every three years for these workers who come under its purview. The content of the exams for the silica standard will probably look a little more familiar than what we've just talked about. It's similar to what comes under the asbestos standard. There needs to be a medical history and a work history, physical examination with the obvious emphasis on the respiratory system, a chest X-ray or more likely a digital radiograph, and that has to be read by a NIOSH certified B-reader according to the ILO classification. If that B-read shows opacities, mainly early or simple silicosis of 1, 0 or higher, then the worker has to be referred to a board-certified pulmonologist or an occupational physician for additional evaluation. There needs to be pulmonary function tests. They are required to at least measure two main parameters, force vital capacity and FEV1, along with the ratio. A TB test, usually a PPD skin test, should be done, but it's only required on the initial exam only. And of course, as in many standards, any additional tests that are deemed appropriate by the examining physician. The medical reports and opinions that the workers get are similar to what they get under the OSHA asbestos standard, but a bit more detailed. They get a report with detailed medical findings and of any work restrictions that are suggested or required for that worker. There should be recommendations if there's any further evaluation or treatment felt necessary for the worker, and there should be information about limitation on that worker's use of a respirator or for future silica exposure. Lastly, there should be a statement if it's required. Remember on the previous slide, the chest x-ray, that if there was a B reading that was greater or equal to a 1, 0, in other words, showing some small opacities, has triggered the duty by the employer to pay for a consultation by a pulmonary or an occupational medicine physician. So that is somewhat different than what you see in the asbestos standard and goes along with that. Now these are the reports that the worker is supposed to get, and some of this, much of this in fact, can be limited if the worker, patient, employee doesn't want it to go to the employer, and that worker has to sign a release for the employer to get that information. The medical reports and opinions that the employer is supposed to receive are rather limited, much more like the asbestos standard. They should only describe the limitations of that worker for respirator use and when the next period visit will be, generally in three years, unless there's a reason to see them sooner. As I mentioned in the last slide, if the worker gives written consent for release to the employer, you may provide recommendations on limitations on exposure to respiral or crystalline silica and the examination by a pulmonary or occupational medicine specialist. The worker in general should be asked to give consent for these there, particularly if it regards limitations, but the reason for instituting this in the OSHA silica standard was that individual workers felt that if limitations were reported, that was a sign of possible or likely silicosis, that they would be terminated prior to filing a workers compensation case, or that the employer would then know that there was a likely case of silicosis going on for that. So, this is the reason to require written consent before releasing that to the employer. The examination by the pulmonary or occupational medicine specialist, it's a little bit difficult to, I think, implement in practice because, as you saw from the last slide, that examination by the specialist needs to be paid for by the employer. That's the OSHA standard requires that. So, getting around the question of worker consent to note that they need to be examined by the specialist versus the employer paying for it is one that I don't think has been adequately sorted out as of yet. Moving onward to the OSHA lead standard, the thing to remember here is that there's separate requirements for general industry, which would be, for example, a battery making industry or some other form of industrial work using lead, versus the construction industry, which primarily is involved with either demolition, stripping, or burning paint. Many highway workers come under the purview of the construction standard, for example, but that there are two separate standards, really, and then, therefore, slightly separate sets of requirements for medical surveillance within them, and if you're in doubt, again, just refer to the proper standard. The action level for general industry is fairly straightforward. It's exposure to airborne lead at 30 micrograms per cubic meter on a time-weighted average of 8 hours, and this is without regard to the use of respirator. The standard triggers medical surveillance if employees are exposed at the action level for 30 days out of any 12-month period, and the exam requirements under the general industry standard are to have one prior to assignment, which includes a history and physical examination, blood pressure, laboratory tests, mainly including a blood lead and a zinc protoporphyrin or free erythrocyte protoporphyrin, ZPP or FEP, CBC, renal indices, BUN and creatinine, and a urinalysis with micro. They need an annual medical examination if a blood lead level is greater than 40 in the past 12 months. Otherwise, they just need surveillance with a blood lead level. They also need an exam as soon as possible after employee develops signs or symptoms that are suggestive or indicative of lead poisoning, or if the employee has noted the desire to procreate or to start a family and needs advice about the effects of lead exposure on ability to do so, and they need a medical examination at the end when they're removed from exposure. I'll leave you with a thought. What's the most common cause of an elevated ZPP in US adults? It's in the main the frequency of the exams that differ between the two lead standard. In general industry, it's every six months, and again these are really just for blood lead levels, and every two months, if a blood lead level has been greater or equal than to 40 micrograms per deciliter, unless two consecutive samples are less than 40, then they go back to the six-month standards. In construction, it's done every two months for the first six months, so that would be three times after the initial exam, and then every six months thereafter. They should be done at least monthly for any employee who is on medical removal protection, and we'll see those in later slides, for that elevated blood lead level that kicks in for MRP, and any sample that exceeds the level for MRP, the employer has to provide a second sample from that worker within two weeks after notice is received of a first elevated sample. That's to both recheck and to ensure that it's not going up, and they need to be removed immediately. In the next slides, we'll look at levels that trigger medical removal protection. What does it entail? During the period of medical removal protection, which can be up to 18 months, the employer must maintain that worker's earnings, they must maintain their seniority, and they have to maintain other employment rights and benefits, so that means health care insurance and related aspects of employee benefits. It also means that in terms of things like seniority, if there were promotions due or length of service accrued, the effect of employees' earnings, those have to be maintained as though the worker had not been removed, and as I mentioned, this is for a period of up to 18 months. This doesn't mean that they cannot work, it only means that they cannot work with or around lead exposure. They can pour concrete if it doesn't entail lead exposure, for example, but they have to be paid at the rate that they would have been paid if they continued in their same job. The next two slides are about the blood lead levels that trigger medical removal protection, and this points up one of the differences between the general industry and construction standards. For general industry, a single blood lead level of 60 micrograms per 100 grams of blood or greater, which has to be confirmed by a second follow-up blood lead level within two weeks after the first one, or if the average of the previous three blood lead levels or the average of all of them in the previous six months equals or exceeds 50 unless the last of any of those blood samples was at 40 micrograms or below, or lastly, when in the physician's judgment, continued exposure to lead at the current job would pose a significant risk. So, for example, again, if someone is considering conceiving. So, make a long story short, one blood lead level of 60, average of 50 across six months, basically, or for material impairment and health is the general industry standard. The construction standard, which was promulgated some years later after general industry, is much simpler. It calls for MRP at a blood lead level of 50 micrograms per deciliter or greater, or physician opinion, again, that employee has material impairment to health, for example, from reproduction. This slide just repeats what we had in the prior slide, that the employer has to maintain workers earning seniority and employment rights for a period of up to 18 months under MRP. Again, it doesn't mean that the worker can't work, it just means they can't be working with or around lead where they would be exposed, and MRP ends if there is two consecutive blood lead levels at or below 40 micrograms per deciliter. A little more than a decade ago, a consensus panel reviewed the evidence for health impairment and published a guidance paper in Environmental Health Perspectives in 2006. This is representative of best practices in lead treatment in adults, particularly in workers. It should point out that it doesn't have the force of law or a legal standard, however, it does represent what we now know about impairment to health and might be used as a guidance to material impairment to health. So what it does is suggest removal from exposure of blood lead levels or 30 micrograms per deciliter or greater. And that's really because long-term exposure at those levels is associated with some of the long-term chronic disorders that we saw, hypertension, for example, possibly cognitive impairment, possibly long-standing progressive neuropathy. So again, blood lead level of 30, if two blood lead levels at four weeks are 20 mics per deciliter or greater, and return to work if two blood levels represent or average out to 15 mics per deciliter or lower. And of course, different from the OSHA standard, which maintains that one should keep pregnant women below 30, they should be kept as low as conceivably possible, and certainly below 5 to 10 micrograms per deciliter. And suggestions for chelation, if workers are symptomatic, for example, if they get encephalopathic or if a blood lead level is 100 micrograms per deciliter or higher because of the risk of potential seizures or encephalopathy. So once again, pointing out that these are best practices, there may be some pushback if workers get removed for blood lead levels at 20 or greater. And overall, one of the things this represents are breaks in industrial hygiene and hazard control. And if you do see workers at these lead levels, it's a good bet that those controls are failing and need to be investigated. Moving on from the OSHA lead standard, we come to the OSHA noise exposure standard. And the thing to note here is that there's a variety of mandates of the OSHA noise standard that are in addition to audiometric test requirements. So hearing conservation has to be set up. There needs to be noise monitoring, audiometric testing, which is what we're familiar with, the pursuance of hearing protective devices, or HPDs, training in the workers using them, access and record keeping. Remember from prior slides that the OSHA action level is 85 decibels for an eight-hour time weighted average. That's in distinction to the PEL, permissible exposure level, which, as you remember, is 90 decibels. So the hearing conservation program needs to be instituted at the action level of 85, whereas exposures between 85 and 90 decibels are permissible for an eight-hour time weighted average. This mandates the employer to measure noise either annually or if there's changes in productions, processes or equipment modification that are going to affect or could reasonably be expected to affect noise levels. This slide is another recap of one of the previous slides, and remembering, again, that noise has to be measured, and first incumbent upon the workplace is engineering out the noise exposure so noise control becomes paramount. Audiometric testing, again, has to be performed if they hit the action level, and hearing protective devices have to be issued. Any worker who is found to be in areas where noise exposure is 85 decibels or greater, in other words, the action level, not the PEL, have to be included in a hearing conservation program. We'll see the elements of those in the next few slides and a reminder about the PEL of 90. The standard mandates reduction of noise exposure based on five-decibel increments in noise exposure, so 90 decibels for 8 hours being the PEL. If noise increases to 95 decibels, that needs to be cut to 4 hours, 100 decibels to 2 hours, in other words, with a halving of exposure time for each 5-decibel increase in noise levels, and if you keep on going upward that way, 115 decibels is the short-term exposure limit or STEL, where there's 15 minutes maximum permissible exposure per day. Now again here, I think we pointed out earlier that this is inconsistent with the physics of noise because a 3-decibel increase in noise is equal to a doubling of sound because it's a logarithmic scale, and so therefore technically, and as the EU and Canada do, they have an exchange rate that halves exposure for each 3-decibel increase in noise levels, but this is what's in the OSHA standard, and as a result, it becomes less protective as you go on up the decibel scale and higher volume. Hearing protective devices have to be provided to workers who are exposed at 90 decibels for an 8-hour average at no cost, they must be replaced as necessary, and giving double protection, which would be ear plugs plus ear muffs, should be given if noise levels exceed 110 decibels and on upwards to the STEL. The employer has to ensure that they're worn by required employees, by those who haven't yet had a baseline audiogram, that they're worn at 85 decibels if a standard threshold shift has been detected, and what I didn't mention here is that anyone who is exposed at the action level of 85 decibels can request hearing protection devices, even though they're not mandatory until you hit the PEL at 90. One size hearing protector doesn't fit all people or is useful or easily worn by all workers, so that the employees should be given selection from a variety of suitable hearing protection devices. The employer must provide training and use and care of HPDs for the workers who require them, and they have to ensure proper fit, usually fitted by a safety professional or hygienist who can also supervise correct use. HPDs, as we mentioned from the previous slide, come in a variety of forms. They can be muffs or earplugs. They come with a noise reduction rating, usually stamped on the HPD package itself, and that's an estimate of how much or the extent to which it will reduce perceived noise under ideal conditions. And, again, mileage may vary because no worker may wear them perfectly. They may not fit perfectly. If they do, they may give some reasonable, pretty good attenuation of noise, 15 to 30 decibels, which would be significant, particularly if they could get worker noise exposure down below 85 decibels. That's assuming they're well fitted and used, and often they aren't, or often they're not worn all the time. What are the potential problems with personal protective equipment? By this time point in the course, it should come to mind is that they have to fit right, they have to be fitted well, they have to be used properly every time, and they have to be replaced when they wear out. So, particularly using them properly every time becomes sort of problematic in workers who may not want to or may not be able to use them as indicated every time they're exposed. Audiometry testing must be performed on all employees with exposure at or greater than 85 decibels or the action level. A baseline audiogram has to be performed within six months of first working there or the first noise exposure that that employee sustains. There's an exception for, say, remote companies who must use a mobile van, and that can be up to one year. And then the audiometry needs to be repeated at least annually afterwards for each and every employee who's got continuing exposure to 85 decibels or greater across time, and as with most testing, at no cost to the employee. Audiometric testing programs must be done under the supervision of a licensed audiologist, a licensed tech operating under an MD or an ENT or other physician with some experience in doing it, and there's a requirement for a 14-hour noise-free period before testing for a baseline, so they should probably be tested on a Monday morning, assuming that they didn't have any other hobbies that entailed exposure to noise. So that baseline is then compared, I think as we mentioned in the hearing section earlier on in this course, and there's an allowance or correction for age or presbycusis allowed in comparison for the baseline audiogram so that aging will lop a little bit off the difference when you're calculating a standard threshold shift. Here again to remind you is the definition of a standard threshold shift, and that shift is an average that's greater than 10 decibels in the mean values using the 2, 3, and 4 kilohertz frequencies, and that mandates a retest within 30 days, and that is OSHA recordable if that difference from baseline remains at 10 decibels and the overall mean threshold at those levels is greater than 25 decibels. Refer back to the hearing lecture that we did before, and then that becomes the new baseline for comparison, so from then on, if there's continued hearing loss, there might still be another reportable threshold shift later on. The OSHA standard has requirements for notification of the worker. If there's a proven repeatable standard threshold shift, that employee must be informed in writing within 21 days of which it was determined unless there's a physician determination that that STS was not work-related or not aggravated by occupational noise exposure. The employer must ensure some further steps that are taken when an STS occurs, and we'll look at them in the next slide. Fundamentally, as with most surveillance examinations, a high value in the hearing case standard threshold shift indicates a break in control procedures, whether it's industrial hygiene, noise control, some type of control of hazards at the workplace is not working, so that employees who are not using hearing protectors need to be fitted with hearing protection devices trained and required to wear them if employees develop an STS, and if they're already using HPDs, they need to be refitted and retrained, and if possible, if there's evidence that the HPDs are not giving them the proper protection, they need to be given better hearing protection and better attenuation out of their HPDs. If there's a feeling from this that additional evaluation is necessary, the employee needs to be referred for a clinical, basically a greater audiological evaluation or an ENT examination if there's additional testing necessary or if there's evidence that there's possible medical pathology of the ear causing or aggravating or aggravated by the wearing of hearing protection, and the employee needs to be informed of the need for an ENT exam if there's evidence of medical pathology of the ear that's unrelated to the use of hearing protectors or to the noise exposure that they're sustaining. Moving on from hearing, we come now to discuss the OSHA asbestos standard, and as with silica, which is more recent, there are two asbestos standards, those for general industry and requirements for construction, and it depends upon either activity or levels of a contaminant. In the general industry standard, there's a specified time-weighted average for asbestos in the standard, and that is 0.1 fiber per cc of air as an eight-hour time-weighted average. This has dropped across the years. The initial asbestos standard specified two fibers per cc, and then that was cut down further several times, and asbestos is regulated primarily now as a carcinogen rather than via the hazards of fibrotic lung disease. So this is the reason for the 0.1 fiber asbestos standard, exposure standard. The excursion limit that they're permitted to have high for a specified period of time is one fiber per cc for 30 minutes, and if it exceeds that, then workers need to be pulled. I won't do the calculations for you there, but one exercise you might do is to consider how many cc's of air a worker breathes during a day and figure out how many asbestos fibers might be breathed in given that asbestos standard. Did you work out that problem on the last slide? Anyway, a worker at the workplace probably breathes about three cubic meters or three million cc's of air in a workday doing light work, and that worker could breathe in 300,000 asbestos fibers per day, every day, and still be below the OSHA standard. So this is probably not in the realm of causation for fibrotic lung disease, but because asbestos is regulated as a carcinogen, one may look at this and consider it not 100% protective of the risk of cancer over a working lifetime. Moving on to the required examinations under the asbestos standard, you can't use a regular pre-placement examination to satisfy the OSHA standard unless the cost of the exam was borne by the employer, and what I don't say here is that it had to encompass the baseline requirements of the asbestos standard, particularly with spirometry and chest x-rays. There needs to be periodic and annual examinations, and there needs to be a termination of employment examination unless the employee has had an equivalent asbestos standard compliant exam within the previous year. So pre-placement, annual, and a termination of employment. What does the asbestos standard require as the content of an exam? It requires a medical and work history, of course, with emphasis upon their exposure to asbestos, a physical examination, and of course, emphasis on the respiratory system, cardiovascular system because of risk of pulmonary fibrosis and the effect on the heart and the digestive tract, which also may be susceptible to cancer under the exposure conditions. They need to complete a respiratory disease standardized questionnaire. You may have seen these or be familiar with them. They inquire about cough, sputum production, and the like. A chest x-ray is required. Those of you who certified 10 years or so ago probably remember that about 10 years ago in the advent of digital radiography, there was a lot of questions with no particularly good answers yet about how digital radiographs were going to be read under the ILO or B-reading standards. So digital radiography has been allowed in place of traditional chest films, and they really were films, for about 10 years now, a little bit less than that there. So there are provisions for digital radiography reading according to the B-reading protocols. Pulmonary function tests, so an FVC and an FEV1 need to be tested and recorded. And the usual application of any OSHA standard, any additional tests that are considered appropriate by the examining doctor. This slide gives you a chart of the frequency of required chest x-rays under the asbestos general industry standard, and it's based on two axes, the years since first exposure and the age of the asbestos worker. And so this ranges in young workers with less than 10 years exposure, beginning every five year intervals between chest x-rays and moving on upward as the employee ages and the years since first exposure approach or go over 10 years, the frequency required falls to two years and then every year for workers age greater than 45 with over 10 years exposure. The OSHA standard requires reading of the chest x-rays according to the ILO interpretations, and it mandates that these chest x-rays be interpreted by a B-reader, but they also, if a B-reader is not available or someone with expertise is doing that, they could be board eligible or certified radiologists or experienced physicians, primarily pulmonologists who have known expertise in pneumoconiosis. At the end of the asbestos exam, the standard mandates that a physician's written opinion be made and provided to the employer and of course to the worker. And remember that OSHA does not mandate the practice of medicine. Again, these are written in stone and medicine is an ever-moving target, so they don't say what you need to do if you find abnormalities. Obviously, the worker is going to need advice, potentially need treatment if there's evidence of asbestosis or indeed a malignancy found on the examination, but the standard doesn't mandate what to do about those. What they do is they mandate that you inform the employee and the employer as to whether there are any detected medical conditions that place the employee at increased risk of impairment to their health from exposure to asbestos. I think we can guess what that means is that if there's evidence of asbestosis, pulmonary fibrosis, or certainly cancer, that they do have a condition that is concerning enough to potentially keep them away from further exposure. That written opinion also has to include recommended limitations on the employee or whether or not the employee is permitted or has limits on the use of personal protective equipment, mainly including respirators, but it may also be protective clothing, and a statement that the employee has been informed by the doctor of the results of the medical examination and of any medical conditions that arose from asbestos exposure that require further explanation, referral, or treatment. And lastly, but also importantly, you need to include a statement that the employee has been informed by you that there's an increased risk of lung cancer that's attributable to the combined effect of tobacco smoking and asbestos exposure. So if you think back to the pulmonary lecture about what we know about the synergy between cigarette smoke and asbestos exposure, remember that it is synergistic multiplicative and presents at high doses asbestos exposure in high-dose smokers relative risks for cancer that may be as high as 50. So this is important, and of course, left unsaid here is the fact that you should probably make efforts to get your patient or the surveilled worker to stop smoking as much and as quickly as possible. Moving on to some of the last of our surveillance standards, we come to the OSHA benzene standard. The thing to remember about benzene is that exposure causes marrow suppression, pancytopenia, and potentially leukemia. So the emphasis in the benzene standard is going to be primarily on the hematopoietic system and on blood counts. Again, requirements for initial exams prior to exposures and annual examinations for workers who remain exposed to benzene, emergency exams, which we'll talk about in the next slide, and an exit exam at the end of exposure and working. The OSHA medical exams for benzene are fairly simple compared to some of the previous ones we've seen. They consist of a history, particularly a history of bleeding, blood disgraces, blood abnormalities, hematologic disorders, and the like, and a physical examination, which you can imagine is probably not very revealing in the majority of cases. And the main laboratory testing the benzene standard requires is a CBC with a differential platelet count and red cell indices. So you want to have both the indices and the counts in a CBC, but also a differential to look for the possibility of abnormal leukocytes. I should say it says current benzene exposure. I want you to cross that off and write emergency benzene exposure. So the standard generally for annual exams or the initial exam doesn't require a metric for measurement of benzene or benzene metabolites, things like tt-muconic acid, but what it does require is if there's emergency exposure to benzene that would entail a benzene spill or an accidental exposure somewhere within a factory. It requires that that worker be sent for a urinary phenol at the end of the shift to gauge the metabolites of it. Now phenol is probably one of the less sensitive metabolites in the urine for benzene exposure, but it's what the OSHA standard says. You may on your own initiative want to look at other metabolites again such as tt-muconic acid. The standard then mandates that if a urinary phenol test is greater than 75 milligrams per liter of urine that that worker have a CBC with differential and a platelet count every month monthly for a period of three months to look at the possibility of acute marrow suppression stemming from that emergency exposure. As we wind down to the end of surveillance, I'm providing here a couple other examples of testing and surveillance programs and some of these we've seen across the course of some of the other lectures. If you remember the lecture on renal disease we talked about the OSHA cadmium standard that mandates measurement of cadmium in blood and urine and most importantly mandates the measurement of small molecular weight proteins in the urine beta-2 microglobulin specifically and that's an index of proximal tubule dysfunction and incipient renal disease. The cotton dust standard which generally results in obstructive lung disease which may progress to fixed obstruction requires that bracketed spirometry be done on the first day of the work week so pre-shift workers show up at eight o'clock at the mill or cotton factory and they get a spirometry prior to starting work on the first day of the work week usually after a weekend off and a second spirometry at the end of that day and a significant drop usually about 10 percent in FEV1 may indicate that there's obstructive disease consequent to their exposure in the factory and just to remind you of the previous slides the benzene standard in case you've forgotten requires CBC with peripheral smear and a manual differential. Slightly unusual standard in terms of the tests that are required under the standard is the OSHA arsenic standard so it requires for initial medical evaluations and periodic testing a work history and a physical examination similar to other standards a chest x-ray used to again be a 14 by 17 PA but there's digital radiography now nasal and skin examination and a sputum cytology examination so all of this is targeted to what it's targeted to the fact that arsenic is regulated here primarily as a carcinogen so you're looking for evidence of lung cancer evidence of skin cancer or sinonasal cancer again the sputum cytology along with the chest x-ray looking for lung cancer and I think amongst other examinations if you wanted to be slightly compulsive about it you may consider looking at a urinalysis or further along if workers have been exposed for a long time urine cytology because the other possibility might be bladder cancer here but certainly skin and lung cancer for arsenic now what strikes you as unusual about this standard take a moment to look at that what might have struck you as being unusual from the previous slide is that the OSHA arsenic standard doesn't require biological monitoring for arsenic there's no requirement for blood arsenic or urine arsenic now remember from previous slides in this course urine arsenic has what it's got a very very short half-life it's going to have life in urine of about 10 hours which means that if you're catching workers even on say a Monday morning what's going to happen is that those won't be really reflective of occupational arsenic exposures it's passed through the body very quickly and so while urine testing is a feasible way to measure arsenic there's also some other pitfalls which we'll look on the next slide and here's one of the other reasons why the OSHA standard doesn't mandate testing urine arsenic this looks like a complicated slide but it's relatively simple let's break it down somebody is tested for urine arsenic at time zero and then fed a nice shrimp meal sometime between time zero and the end of day one urine arsenic is measured again and what happens the total arsenic measured in the urine has gone up by a factor of 100 and the arsenic in urine has gone from about maybe 15 or 20 micrograms per liter to a thousand micrograms per liter at the end of day one and kind of comes down this is a logarithmic scale so it does come down fairly quickly there afterwards if you measure or speciate or separate out the inorganic arsenic in other words the toxic part whereas organic arsenic which is in seafood is non-toxic if you speciate out that inorganic arsenic it's those two solid lines along the bottom of the chart which have stayed about the 15 to 20 range even after the shrimp meal so urine arsenic tests are confounded by eating particularly shellfish and many kinds of other seafood food so there's two ways to go if you're measuring urine for arsenic doing biological monitoring for it what you're really concerned about is inorganic arsenic because that's the toxic species of arsenic the organic stuff is what's in shellfish and it's not particularly toxic so you can order speciated arsenic determinations which will distinguish between the organic arsenic and the inorganic arsenic and determine whether an elevated urine arsenic is due to eating shellfish which is benign or is from exposure to inorganic arsenic the poor doctor's way of course would be to tell them to refrain from eating shellfish or the like for a period of about five days to a week and then measure it again if you didn't want to speciate it but speciation doesn't cost a ton extra there and it actually gives you a chance to put some hard numbers on it there and many people as i'm sure many of you have had already will be referred to you for an elevated arsenic level which on speciation turns out to be the result of eating seafood going around to the earlier slides that we saw in this lecture remember that OSHA has medical surveillance requirements for about 30 specific substances however you may work with companies processes exposures where there's non-mandated medical surveillance but that it represents good practice so what you want to do is look for example at the ACGIH requirements look for BEIs look for other exposure standards developed by other organizations and the EU also has some exposure limits and exposure criteria for many of these other non-mandated surveillance type of exposures a somewhat more unusual OSHA standard which we'll deal with last is the hazardous waste operations and emergency response standard or the HAZWOPER standard to make a long name short and these are workers who are exposed to a large variety and possibly changing variety of different chemicals and materials so for example the county sheriffs may have emergency responders who need to medical surveillance exams these sheriff's deputies have been assigned to secure cordon off hazardous material spills until the decontaminated and cleaned up by contractor employees so the big question for you is what sort of medical examinations do you need and what sort of materials do you need to test for under the HAZWOPER standard simple parts first in the HAZWOPER standard the frequency of examinations so workers who are going to be emergency response personnel and doing some of the work that we saw the previous slide must be examined prior to assignment to those jobs they must be examined at least once a year unless the attending physician believes that a longer interval up to two years is appropriate they may be all young healthy people as soon as possible if there's been a significant exposure or an injury from a spill and a termination if there hasn't been an exam within six months so that was the easy part of the HAZWOPER exam here's the hard part of the exam the content of medical examinations shall be determined by the attending physician they do publish guidelines and a guidance manual for hazardous waste site activities and they ask you to consult that within the OSHA standard but the bottom line here is it's down to you and you want to know what these individuals will be working with so here's what you need to ask yourself is first off what tests are suggested by that manual in the appendix of the standard and you want to take that and match it with what are the most likely chemical exposures that the sheriff's deputies may have so many of these exposures may be acute irritants there may be ammonia gas there may be chlorine spills etc etc those probably aren't reasonably well tested for but you also want to think are they going to be exposed to hydrocarbons and gasoline some of which may include benzene for example will they be exposed to asbestos in the course not of moving vehicles but in old areas where asbestos was used as insulation might they be exposed to noise or hearing problems not exactly a chemical exposure but something to consider and then lastly and oftentimes sometimes oftentimes these exams become something of a medical benefit for these workers do you or will you include tests that aren't related to harmful effects of potential chemical exposures and also do you include tests that are not specific to chemical exposures but are indices of physiologic function that might be revealing with exposure to chemicals given the fact that they're all so non-specific what do i mean by that fancy language i mean liver function tests cbc's test of renal function and then for the quote-unquote benefit aspect of this do you test cholesterol for example and so for the group of workers who we saw in the initial slide vignette about who's getting it here's what might be a reasonable approach to the haswhopper standard taking a work history doing a physical examination obviously because they're going to be looking primarily at things like tanker spills there really aren't many good tests that relate to exposure that you could test for that indicate hydrocarbon or fuel oil toxicity so fundamentally you're going to be looking at indirect testing for these workers cbc's blood chemistries such as lfts and urinalysis the second point you want to remember that is actually not related specifically to the toxicity of exposure but is related to the work that they're going to do is to evaluate the cardiovascular and respiratory system with respect to their ability to wear impermeable clothing and a self-contained breathing apparatus so now we've come around kind of full circle to what we talked about at the beginning set of slides which was the osha personal protective equipment or fundamentally the respirator standard and again if these are individuals who might be working in heat limiting impermeable clothing they may need to get spirometry they may need to get screening electrocardiogram but again they're going to be young people maybe they should be on a treadmill to exclude people who may have poor exercise tolerance again that may be not necessarily as specific as one would like it but they should get part of their examination directed towards the ability to wear a scba in particular and then for periodic medical examinations you should probably be looking at much the same thing work history particularly how work has gone in the past year and whether there were any problems performing the work a physical examination again repeat organ function testing particularly dependent upon the exposures that they did sustain and again this is a group who are exposed to hydrocarbons and so some of the same tests might obtain and then potentially repeating spirometry maybe treadmill testing depending upon how the initial evaluation went and most particularly depending upon their work history that they provide you or that the employer provides you about whether they had any difficulties accidents or injuries during the interval period from the first exam to this periodic examination so right there concludes the very last set of lectures for this course we hope that you've enjoyed the course we look forward to your feedback on it and we'd be very interested in knowing whether or not we did cover for you the materials that are on the examination whether it be the research examination or the primary exam and lastly from ACOM, Dr. Litto and myself we wish you good luck on the examination and please don't hesitate to contact us if there are any questions

OSHA medical standards

surveillance requirements

workplace exposures

health effects

lead exposure

noise exposure

asbestos exposure

benzene exposure

hazardous waste operations

medical surveillance criteria

chemical exposures