Sarah Bauder is the senior editor at Lab Manager. She possesses a diverse background spanning editorial, digital marketing and film and television production. She brings over 15 years of experience
Jonathan Klane, M.S.Ed., CIH, CSP, CHMM, CIT's EHS and risk career spans more than three decades in various roles as a consultant, trainer, professor, embedded safety director for two colleges.
Ask how a particular risk is managed in almost any laboratory, and the answer usually comes back in two dimensions: severity (how bad the outcome could be) and probability (how likely it is to happen). This is the classic logic of the familiar risk matrix. It is not inherently wrong, but according to Jonathan Klane, it quietly skips over the one factor a lab manager can most directly control: exposure. Klane, who has directed safety for hundreds of research labs, advises as a principal consultant with the global sustainability consultancy ERM, and is now a PhD candidate at Arizona State University, made the case at the 2026 Lab Manager Leadership Summit for treating exposure as its own factor. Severity is usually fixed by the hazard itself, and probability is stubborn because it rides on human behavior—and as any lab manager knows, "humans aren't good at being controlled." Exposure is different. Exposure is where the work of control actually happens.
In the standard two-factor model, exposure gets absorbed into probability and disappears. Klane argues it should stand on its own, giving lab managers a three-part equation: severity times exposure times probability. Pulling exposure out is not academic hair-splitting—it changes where a manager looks for solutions.
Exposure, in Klane's framing, is fundamentally about proximity, and proximity comes in two forms. There is the literal question of how physically close a person is to a hazard. "Is my head inside the fume hood?" he asked, naming the thing every lab manager has seen and winced at. And there is the figurative question of whether something sits between the person and the hazard. "Do I have barriers, such as a sash, such as a respirator, such as a, you know, fill in the blank, you know, explosion shield?"
The principle underneath both is one of the most reliable in all of safety. "Distance is your friend," Klane said, because the energy from many hazards, such as radiation or noise, drops off with the inverse square of distance. Move away, and the risk falls fast. Put a barrier in place, and the exposure falls whether or not the incident ever becomes more or less likely. That is the point managers miss when they collapse exposure into probability—the two do not move together, and treating them as one hides the lever that is easiest to pull.
The hierarchy of controls, and the line running through it
Jonathan Klane, MSEd, CIH, CSP, CHMM, CIT, storytelling consultant.
The framework Klane returns to again and again is the hierarchy of hazard controls, the ranked ladder of safety measures that runs, in order of effectiveness, from elimination and substitution at the top down through engineering controls to administrative controls and, at the very bottom, personal protective equipment. The order matters because the top is where hazards are actually removed and the bottom is where they are merely guarded against. As Klane put it, by the time a lab is relying only on PPE, if it fails, "the hazard is going to be hitting the person, whatever that hazard is." That ranking is not his invention—it mirrors the hierarchy of controls maintained by NIOSH, the federal framework that places elimination and substitution above engineering controls, and all of them above PPE.
Yet, the insight Klane presses hardest is a line most managers never notice. "There's a break right here under engineering controls," he said. "The rest are human when you think about it." Everything above the line, up to and including the fume hood or the gas cabinet, controls the hazard through physical means that do not depend on a person doing the right thing in the moment. Everything below it, such as work practices, procedures, training, signs, and labels, depends entirely on human behavior. That split is worth keeping in view:
Above the line (physical controls): Elimination, substitution, isolation, and engineering controls such as fume hoods, gas cabinets, and biosafety cabinets, which contain the hazard whether or not anyone acts correctly.
Below the line (human controls): Work practices, administrative controls such as procedures, training, signs, and labels, and PPE, all of which work only when people follow them every time.
For a lab manager deciding where to invest limited time and budget, that line is a map. It shows which controls will hold on their own and which will only work if people cooperate every single time.
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This is also why substitution is so powerful and so underused. When a lab swaps leaded solder for a non-leaded alternative, Klane noted, the process stays intact but the severity of the consequence collapses. The manager has not added another fragile human step—they have engineered the danger out closer to the source.
Engineering the distance: real controls for real hazards
The abstract principle becomes concrete the moment you look at how labs actually contain their worst hazards, and Klane's examples are worth walking through because each one is a lesson in exposure.
Consider soldering with lead. A researcher can work at an open bench, at a snorkel exhaust, or inside a three-sided HEPA-filtered hood. Each option changes the exposure without touching the toxicity of the lead itself. Klane is candid that intuition can mislead here. Snorkels, the flexible capture arms that seem so protective, are weaker than they look. "Take one match and see how far away you can hold it and blow it out," he said. "Now take another match and just see if at that distance you can suck it out. You can't." A snorkel is a vacuum with a very short capture distance, and treating it as if it reaches farther than it does is exactly the kind of exposure misjudgment that gets people hurt.
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Gas cabinets tell the same story from a different angle. With a toxic gas like carbon monoxide, Klane pointed out, putting the cylinder in a ventilated gas cabinet with an integrated sensor and a critical orifice does not change how deadly the gas is. It changes the exposure and the probability by containing a leak and shutting it off automatically. He is quick to note that a handheld meter, useful as it is, is not the same as a fixed sensor. "If you hear it, you're probably now dead on the floor," he said of relying on noticing a CO leak. The control has to be built into the system, not carried in a technician's hand.
When the barrier is the last thing standing
The stakes of getting exposure right are clearest with the hazards that punish a single lapse, and here Klane's favorite cautionary example is hydrofluoric acid. HF is not merely corrosive—it is insidious. It seeks out the calcium in the body, and a seemingly minor skin contact can become fatal as the acid robs the body of the calcium it needs to run the heart. Every HF exposure, Klane stressed, is a trip to the hospital, and labs that use it must keep calcium gluconate, the antidote, on hand to apply immediately rather than waiting for emergency responders.
HF is a lesson in why the layers of control have to be designed with the worst case in mind. It is also a lesson in the limits of PPE, the bottom of the hierarchy. Gloves are a barrier, and barriers reduce exposure, but only the right barrier against the right hazard. Klane's illustration is chilling in its simplicity. Nitrile gloves, ubiquitous in labs and treated by many researchers as protection against everything, are permeated by dichloromethane on a molecular level. The glove looks intact while the chemical passes straight through it. The most tragic version of this, he noted, was the death of a Dartmouth chemist who was exposed to dimethylmercury that passed through her latex gloves—by the time it entered her body, nothing could be done. "There is no antidote," Klane said. A barrier that does not match its hazard is not a control at all. It is a false sense of one.
Reading the three factors in every change
The practical payoff of separating exposure is that it gives a manager a disciplined way to evaluate any proposed change. When Klane walks through his exercises, the recurring question is not "is this safer?" but "which factor did we just change?" That precision keeps managers honest about what a given intervention actually buys.
A few patterns emerge that are worth carrying back to the bench:
Substitution changes severity. Swapping a high-hazard material for a lower-hazard one, like leaded for non-leaded solder, attacks the consequence itself.
Engineering controls and barriers change exposure. A fume hood, a HEPA hood, a gas cabinet, or a sash reduces how much of the hazard reaches the person, regardless of likelihood.
Enclosure and interlocks can change probability too. A ventilated gas cabinet with an automatic shutoff lowers the odds of a leak reaching anyone, on top of reducing exposure.
PPE is the last layer, not the first. Gloves and respirators reduce exposure only when matched precisely to the hazard, and they fail closest to the person.
The value of naming the factor is that it stops managers from congratulating themselves for a change that only looked like progress. Adding a respirator when an engineering control was available, for instance, trades a strong control for a weak one while feeling productive.
What this means for lab managers
The quiet argument running through all of this is that risk control is a craft, not a checklist, and its most useful tool is often ignored because it hides between the two factors everyone already tracks. Severity is largely handed to a lab manager by the nature of the hazard. Probability fights back because it rides on human behavior. Exposure is the factor a manager can engineer, layer, and verify, and it is where the hierarchy of controls does its real work.
For lab managers, the shift is one of attention. Instead of asking only "how bad and how likely," the better question is "how close, and what stands between my people and the hazard?" That question leads directly to fume hoods and gas cabinets, to the right glove for the right chemical, to the antidote on the shelf, and to the difference between a barrier that holds and one that only appears to. Perfection is not the goal, Klane would be the first to say. Yet, a lab manager who masters exposure control holds the single most effective lever for ensuring a hazard never reaches a human being.
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Frequently Asked Questions (FAQs)
What is the hierarchy of hazard controls?
It is the ranked order of safety measures from most to least effective: elimination, substitution, engineering controls, work practices, administrative controls, and personal protective equipment. Controls above the "engineering" line work through physical means, while those below it depend on human behavior, which is why PPE is considered the last line of defense.
What are the three factors of risk in a laboratory?
The three factors are severity (how bad the outcome could be), exposure (how close a person is to the hazard and whether a barrier separates them), and probability (how likely the event is). Many assessments use only severity and probability, but separating out exposure reveals the factor a lab manager can most directly control.
Why is exposure the factor lab managers should focus on?
Severity is usually fixed by the hazard itself, and probability is hard to control because it depends on human behavior. Exposure, by contrast, can be engineered through distance and barriers such as fume hoods, gas cabinets, and the correct PPE, making it the factor a manager can most reliably change.
Why aren't nitrile gloves enough to protect against all chemicals?
No single glove protects against every chemical. Some substances, such as dichloromethane, permeate nitrile on a molecular level while the glove appears intact, and dimethylmercury permeates latex. Choosing chemical protective equipment means matching the specific glove material to the specific hazard rather than assuming one type works universally.
Sarah Bauder is the senior editor at Lab Manager. She possesses a diverse background spanning editorial, digital marketing and film and television production. She brings over 15 years of experience in editorial writing, B2C and B2B content creation. A student of history, she graduated from York University in Toronto, Ontario, Canada. She can be reached at sbauder@labmanger.com.
