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  • Hello. Welcome to "Occupational Hygiene Principles". My name is Pete Raynor.

  • I’m an Associate Professor at the University of Minnesota School of Public Health.

  • The learning objectives for this module are that, by the end, learners should be able to classify the types of hazards that workers face,

  • define exposure and related terms, list the routes by which workers can be exposed to hazardous agents,

  • and describe the occupational hygiene framework of anticipating, recognizing, evaluating, and controlling workplace hazards.

  • As we begin to discuss the occupational hygiene framework, I should make the point that "occupational hygiene" is a term used

  • interchangeably with "industrial hygiene". "Occupational hygiene" is used more frequently in Europe and other parts of the world

  • whereas "industrial hygiene" is used more commonly in the United States.

  • I'm primarily going to use "occupational hygiene" in this module because I think it describes the profession more accurately.

  • The American Board of Industrial Hygiene defines industrial hygiene as "the science of protecting and enhancing the health and safety

  • of people at work and in their communities”. This definition makes sense from the standpoint of protecting people at work.

  • However, it also includes another critical aspect of occupational hygiene:

  • the protection of people in the community who may be affected by what others do at work.

  • Goelzer defines occupational hygiene as "the science of the anticipation, recognition, evaluation,and control

  • of hazards arising in or from the workplace and which could impair the health and well-being of workers,

  • also taking into account the possible impact on the surrounding communities and the general environment."

  • This second definition of occupational or industrial hygiene is more comprehensive.

  • I also like that it includes the occupational hygiene framework of anticipating, recognizing, evaluating, and controlling hazards.

  • We need to be able to understand when potential hazards may be present, notice them when they are there,

  • know how to determine if they are a problem, and then do something about them if they are a problem.

  • With whom do occupational or industrial hygienists interact?

  • They interact with people on the job. Most important are the workers.

  • However, this also includes the owners, managers, and supervisors of different workplaces without whose support we can get

  • little accomplished, regulators like those that work for the Occupational Safety and Health Administration or OSHA

  • at either the federal or state level, and members of the public who may be affected by what goes on at the worksite.

  • Occupational hygienists interact with their colleagues in other health and safety fields including occupational physicians,

  • occupational health nurses, safety and environmental specialists, occupational epidemiologists,

  • and occupational hygiene technicians who may carry out some of the measurements and sampling that are designated by hygienists.

  • Finally, occupational hygienists also interact with engineers and facilities and maintenance personnel.

  • Engineers may be tasked with carrying out changes in workplaces to make them more healthy or safe,

  • and facilities and maintenance personnel can affect workplace health and safety by the regular maintenance they conduct,

  • the cleaning that they do, and other changes that they may make to work environments.

  • Let’s talk next about anticipating and recognizing hazards.

  • The way I'm going to do that, at least initially, is to talk about my high school job

  • I worked at a grocery store in Irondequoit, New York, a suburb of Rochester.

  • I worked there from late in my junior year of high school through the summer after my sophomore year in college.

  • When I went to work at the grocery store, my first job there was to collect carts outside.

  • Today, many cart pushers have automated, battery-powered pushers to move trains of carts.

  • Back when I did the job, I worked much like the person in this image: we assembled long trains of carts and pushed them across the parking lot.

  • So, there was a lot of a heavy pushing, and there was also a chance to get your fingers pinched between the carts.

  • It was hard, tiring work. We would sometimes make very long trains of carts on purpose to see how long we could make the train and still

  • push it back to the front of the lot. Sometimes, the long trains got a little out of control and hard to stop because they had so much momentum.

  • We had to be concerned about vehicles in the parking lot. Often, the parking lot was congested, particularly at busy times around

  • holidays or on weekends. Although I was never injured by an incident with a car, there were many close calls and I had to watch myself

  • around cars that were moving too fast or were having difficulty backing out of a parking space.

  • During different times of the year, we were exposed to either heat or to cold. Because Rochester, New York is on Lake Ontario,

  • we had a lot of lake effect snow and frequently it would be slippery in the parking lot during the winter in addition to it being cold.

  • In the summertime, it could be very hot and we would feel it after four hours of pushing carts around.

  • We would sometimes be faced with shoplifters when we worked outside the store.

  • On one particular occasion, I was collecting carts on a sunny afternoon.

  • I was out there by myself, it wasn’t very busy, and I was off in my own little world as I was picking up carts.

  • So, I wasn’t really paying too much attention to what was going on other than in my own immediate vicinity.

  • Suddenly, I saw this guy running toward me, and as he got closer, he yelled to me, "Don't do it, man! Don't do it!" I'm thinking to myself,

  • "Don't do what?" The guy ran past, and I was still trying to understand what he meant, when my supervisor runs up to me and says,

  • "Pete, why didn’t you stop him?" I thought to myself, "Stop what?" I had no idea what was going on. It turned out that he was a shoplifter.

  • So, there was a risk that, had I realized what was going on and tried to intervene, I could've been subjected to some violence.

  • My supervisor was a little disgusted with me for not divining that I should have stopped the guy.

  • This particular supervisor didn’t like me very much, and it was sometimes stressful to deal with him.

  • Eventually, I was given the opportunity to move inside, at least most of the time, and be a checkout clerk, which involved scanning a lot of

  • items, putting them into bags, and lifting the bags up and over a shelf to put them into the customersshopping carts.

  • I would also have to enter numbers into the keypad on the register. Shifts on the registers could last as long as eight hours with

  • a lunch and two short breaks. Standing in one place and repeating these same actions over and over was tiring.

  • One of the other things I would sometimes do when I worked inside was to go to the

  • back room of the store and bring sacks of paper bags – 500 per sackup to the front end.

  • We didn’t have plastic bags back then, so these were thick paper bags.

  • I would take a large cart to the back room, go into the truck trailer where the sacks were stored,

  • climb a pile of sacks, toss about 15 sacks from the pile onto the bed of the trailer,

  • pick the sacks up and pile them onto the cart, and push the heavy cart through the store to the front.

  • Once there, I would have to unload sacks by each register, open the sacks with a box cutter, and stack the bags in the storage area

  • below the register where the clerks could pull them out and use them for customers. It was a pretty tough job.

  • When I worked inside at the front end, there was always a chance that we would have to deal with those shoplifters.

  • One time, a couple of us chased after some shoplifters who were trying to steal beer late at night.

  • We got out into the parking lot and found that we were a little outnumbered because the shoplifters were part of a larger group.

  • Fortunately, the shoplifters and their friends decided to leave the beer on the ground and drive away rather than forcing a confrontation.

  • Another time, several of us were working up front, and a car pulled up outside the front window of the store right near us.

  • A bunch of guys piled out of the vehicle after popping the hood, and we could see that there was a fire in the engine compartment.

  • We were, naturally, concerned about this, as you might expect. After a frantic few seconds discussing what we should do,

  • I ran out of the store with our fire extinguisher and put out the fire, trying to keep as far away as I could.

  • We were surprised about 10 minutes later when the guys piled back into the car and drove away.

  • I'm not sure how far they got; it was a topic of discussion for my co-workers and me for the rest of the evening.

  • Among some of the other duties I had was occasional maintenance work, especially on weekends.

  • There was one time on the Monday of Labor Day weekend that I had to clean both the men's and women's bathrooms for the store.

  • It was clear that they had not been cleaned since the previous Friday, and it was a pretty eye-opening experience

  • to have to clean those restrooms after that amount of time. In short, it was not a fun job.

  • There was lots of nasty stuff in the bathrooms, and a variety of cleaning products needed to be used.

  • Another one of my occasional tasks was to take materials to the back room to be disposed of.

  • Large groups of fluorescent bulbs are changed out at the same time in stores to make the task easier logistically.

  • This was the early 1980s: the fluorescent light bulbs were not recycled at that time.

  • When I was asked to dispose of the bulbs that had been changed out, I would take barrels full of them back to the trash compactor in the

  • back room, pile them into the trash compactor, close the door to the compactor room, press the button to turn the compactor on,

  • and we would then hear the bulbs shatter in the compactor. As a teenager, this was a pretty cool thing to hear all the crashing and smashing

  • and eventually, after the compactor had stopped, we would open the door,

  • and we could see an almost magical haze of shiny glass particles floating in the compactor room. It was awesome to look at, man!

  • Probably the most fun I had on the job was on one full-day shift on the Saturday after Thanksgiving when my co-worker Todd and I

  • had the opportunity to hang holiday decorations for the entire day. We climbed ladders and reached out to hang things across the ceiling,

  • We climbed ladders outdoors and hung garlands and decorations across the front of the store. There was a lot of climbing up and down and

  • reaching this way and that, but it was a really fun day because it was an unusual task to get paid to do. We enjoyed it quite a bit.

  • By this point, you may be wondering, “Why is this guy droning on about his high school job?”

  • Well, let’s think about my job and about the potential hazards that I faced on the job.

  • There were hazards that could have caused unintentional injuries: fires like from the car, vehicles in the parking lot,

  • slips in the parking lot when I pushed carts, falls from ladders when I hung holiday decorations, sharp objects like box cutters,

  • and pinch points like when the carts come together and you pinch your fingers as you try to line them up.

  • In addition to the unintentional injuries, there was a risk of intentional injuries. Violence was a risk particularly when I faced shoplifters.

  • Repetitive motion injuries were quite possible. I faced the risk of an injury to my back from pushing carts,

  • lifting sacks of bags in the back room, and lifting full bags into customers' carts at checkout.

  • Wrist injuries were possible from continually scanning items at the checkouts for long periods of time.

  • Temperature extremes when I worked outdoors, both when it was hot and cold, could have led to heat or cold strain.

  • I was exposed to germs at work. Because I was dealing with members of the public,

  • I could've been exposed to their germs as they sneezed or coughed near me and when I handled their money.

  • There were also the times when I cleaned the public restrooms when there was a potential for exposure to germs.

  • Chemical exposures from cleaning chemicals and the mercury in the fluorescent bulbs could have been a health concern, too.

  • Even stress could have been a concern. I knew that my supervisor didn't like me very much.

  • If I had cared more about the job than I did, I may have felt stress that could have impacted me negatively.

  • There was a whole range of different hazards that I was potentially exposed to in my workplace.

  • Although you may have been able to anticipate that grocery workers face workplace hazards, most of you, unless you've worked

  • a very similar job, would not have been able to recognize all of these different hazards.

  • This is an important point because when you are trying to anticipate and recognize hazards,

  • you really need to get to know the job before you can be effective at analyzing the hazards.

  • Ultimately, workers are the experts on their own jobs. If you are trying to understand where there

  • is a potential for hazardous exposures to whatever sort of agent you're concerned about, you need to talk to the workers.

  • If we generalize and categorize some of the hazards that exist in different workplaces,

  • we can anticipate and recognize chemical hazards that include airborne particles such as nanoparticles.

  • Workplaces may contain different gases and vapors, and especially solvent vapors as many, many solvents are used in industrial settings.

  • Heavy metals may be present, including molten metals, metals used in electronics production, and metals released to the air during machining.

  • A large variety of skin irritants may be present as well, with dermatitis being one of the most common workplace diseases.

  • There are physical hazards, hazards that affect the senses or the whole body.

  • These include noise, ionizing and non-ionizing radiation, and hot and cold temperature extremes.

  • We can anticipate and recognize biological hazards, including infectious disease agents,

  • which can be of particular concern in the healthcare industry, and mold.

  • Agriculture workers may face mold in outdoor environments or in barns,

  • and construction workers may be exposed to mold during renovations.

  • Offices that have experienced water damage may see mold growth in walls, ceilings, and carpeting.

  • There are injury hazards. Unintentional traumatic injuries can occur.

  • These include vehicle crashes, which are one of the most common causes of fatalities on the job.

  • Violence, either among co-workers or involving both workers and people from outside the workplace, is an important occupational hazard.

  • In addition, poor ergonomic conditions, including repetitive motion, awkward posture, and heavy lifting, may lead to musculoskeletal disorders.

  • Occupational hygienists may be able to anticipate, but find it hard to recognize,

  • social and behavioral hazards like stress, sleep deprivation, and substance abuse.

  • These hazards can make it difficult for a worker to perform her or his job safely

  • and in a healthy manner, in addition to being risk factors on their own.

  • and in a healthy manner, in addition to being risk factors on their own.

  • Let's move on and talk about evaluating hazards. Why would we want to evaluate hazards? I list six purposes here.

  • Let's move on and talk about evaluating hazards. Why would we want to evaluate hazards? I list six purposes here.

  • First, we might evaluate hazards for compliance purposes. The goal is to compares workers' exposures to an exposure limit or a standard.

  • For example, we can compare sound levels in a metal stamping operation to the

  • Occupational Safety and Health Administration's permissible exposure limit for noise.

  • We might try to measure levels of a hazardous agent throughout a work environment with a goal of identifying the source or sources of the agent.

  • An example would be to create a concentration map, almost like a topographical map,

  • of a machining facility to identify the sources for emissions of oil mist.

  • In emergency situations, we might seek to detect hazards that are immediately dangerous to life and health.

  • An example is the need to monitor hydrogen sulfide levels when workers enter a manure pit to perform maintenance or cleaning.

  • Control measures might need to be evaluated. The goal in this case would be to ensure that interventions designed to reduce hazardous

  • exposures are working as planned. An example of this is a series of measurements performed to ensure that airborne particles containing mouse

  • urine proteins are kept within ventilated enclosures during the change out of research animal cages in university settings.

  • We might also evaluate hazards as part of research.

  • The goal will depend on the hypothesis that is being investigated, which is sometimes part of a larger occupational epidemiology study.

  • An example of this that I worked on was when we measured silica dust concentrations as part of an epidemiological study

  • to determine the effect of the dust on the lung health of taconite ore miners on the Iron Range in northern Minnesota.

  • Finally, we might evaluate hazards for risk assessment purposes.

  • In a sense, all of these other purposes are forms of informal risk assessments. Here, however, I'm talking about a formal risk assessment

  • where the goal is to calculate exposure and/or dose for a worker exposed to an agent of concern, so that we might compare

  • that exposure or dose to the potential health effects from the dose in order to characterize the risk of an adverse health outcome.

  • An example is to measure radon concentrations in building subbasements to estimate cumulative doses that workers receive.

  • We will talk more about risk assessment and risk characterization in the next module.

  • How do we go about evaluating hazards? One way is by measuring them. We may measure a hazard to detect it, just to see if it is there or not

  • or we may want to know its concentration in a medium like food, water, or, especially in occupational settings, air.

  • In addition to measuring agents in the environment, we can measure things called biomarkers within exposed people.

  • In our context, biomarkers are substances measured in some part of the body that indicate the presence of an agent in the body.

  • A biomarker may include a chemical of concern or its metabolite, or some other biologic indicator of exposure.

  • This "biomonitoring" can be performed on samples of urine or blood or you can measure substances in tissues or hair samples.

  • We can attempt to evaluate hazards using modeling. We are not able measure everything everywhere at all times.

  • One way to get around these limitations is to use mathematical models to estimate exposures. The models can be used to predict

  • concentrations or other relevant measures of exposure as a function, ideally, of both time and location.

  • Ultimately, we will compare these measurements or modeling predictions to some sort of occupational exposure limit.

  • These occupational exposure limits are developed through the risk assessment process,

  • which, as I mentioned previously, will be discussed in a future module.

  • In short, we relate health risk information from toxicological and epidemiological studies to exposure or dose data,

  • decide what is an acceptable risk, and set an exposure limit accordingly.

  • When making measurements after performing the risk assessment,

  • we can compare our findings to the exposure limit to determine whether the workplace may be unduly harmful to people.

  • We can start to discuss controlling hazards by taking a look at some relevant definitions.

  • The vocabulary used may vary depending on one's perspective.

  • We can think about "managing" hazards. Merriam-Webster defines "manage" as "to work upon, or try to alter for a purpose".

  • The term "limit" is defined as "to curtail or reduce in quantity or extent".

  • To "intervene" is "to come in or between by way of hindrance or modification".

  • Finally, to "control" is "to reduce the incidence or severity of, especially to innocuous levels".

  • In many cases, these four words are used interchangeably when talking about ways to reduce exposures.

  • The default word is often "control", but "control" doesn't appeal to some experts because it implies that you are always able to make the

  • changes that you would like to in order to reduce exposures to hazards. The term also lends itself better to technological approaches to

  • reducing hazard levels, whereas words like "manage", "limit", and "intervene" seem to leave open a broader array of approaches.

  • In the way that I use the term "control", I intend to leave open a wide variety

  • of means for reducing exposures, not only technological options.

  • We are going to use the word "control" going forward in this module, but keep in mind that the other words convey equally valuable concepts.

  • We refer to a "hierarchy of control" when discussing approaches to reducing hazard levels.

  • The hierarchy goes from most preferred at the top to least preferred at the bottom. At the top is elimination of the hazardous agent.

  • Can you just completely get the hazard or the process that generates it out of the workplace so that it's not an issue anymore?

  • That option is rarely viable because it would involve removing a process or a product that is essential at that place of work.

  • Next on the hierarchy are engineering controls, which are physical, chemical, or biological changes made to a process or a product

  • that reduce exposures to the hazard. Third on the hierarchy are work practice and administrative controls, which are changes in

  • how, when, or by whom tasks are performed in order to reduce exposures.

  • At the bottom is personal protective equipment, or PPE, devices and garments worn by workers to protect themselves from