Filling the Gaps
Survey Clarifies Needs for Improvement in Exposure Assessment
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Last year, AIHA surveyed OEHS professionals regarding their airborne chemical exposure assessments. On the following pages, The Synergist presents perspectives on the survey responses from John Mulhausen, PhD, CIH, CSP, FAIHA, and Michele Twilley, DrPH, CIH, who helped develop the survey and analyze its findings. During his term as AIHA president in 2021–22, Mulhausen spearheaded several initiatives to advance OEHS science and practice. The survey on airborne chemical exposure assessments was one outcome of these initiatives. Mulhausen is also a contributor to AIHA’s publication A Strategy for Managing and Assessing Occupational Exposures, which provides a detailed explication of best practices in occupational exposure assessment. Twilley, AIHA’s staff industrial hygienist, is the technical lead for various advisory groups and committees and is AIHA's primary technical liaison with outside entities. Twilley also formerly served on the AIHA Board of Directors. More information about the survey is available in a summary of its findings (PDF) and the full survey report (PDF). THE SYNERGIST (TS): Were the survey results what you expected? JOHN MULHAUSEN (JM): There were no huge surprises. We’ve been talking with people about how they practice industrial hygiene for a number of years now and had a feeling that we had some important opportunities for improvement. What I love about these survey results is that they put some hard research behind those feelings. MICHELE TWILLEY (MT): I would agree with that. The only thing I would add is, it was interesting that our English-speaking counterparts across the globe seem to have better adoption of AIHA’s exposure assessment strategy than we do in the U.S. TS: Research has shown that OEHS professionals’ exposure judgments are often wrong and biased low. Do the survey findings offer further support or provide additional context for this research? JM: The survey did not measure the accuracy of the respondents’ judgments, but the results certainly provide context for those research findings. Two things stand out. First, less than a third of us routinely use statistics. Almost two in five, or 38 percent, rarely or never conduct statistical analysis, and 37 percent don’t establish a statistical confidence level for exposure judgments. And second, most of us are still using criteria for determining unacceptable exposures that fail to fully factor in exposure variability and assessment uncertainty. This results in an underestimation of worker risk. TS: According to the survey, six percent of respondents judge exposures to be unacceptable when the average of exposure measurements exceeds the OEL. What were your reactions to this finding? MT: It was startling to see that. It doesn’t even meet the compliance threshold of any value over the OEL being unacceptable. I wondered, did they even understand the question? But when six percent of the respondents, which is statistically significant, had that as the answer, I thought, that’s pretty far from where we want to be. JM: Six percent sounds low, but it is such an extreme example. There are no occupational exposure limits that I know of that are defined as averages of exposures. They’re all defined as limits that we want to exceed very rarely. Those six percent are practicing in a way that surprises me. TS: Based on the survey findings, how would you characterize respondents’ practices regarding similar exposure groups? JM: Because measuring all the exposures of each and every worker is extremely difficult, the systematic use of SEGs is critical to effectively and efficiently characterize and manage worker exposures. Yet only one-third of us systematically define and document SEGs for all workers and airborne chemical agents. MT: I think that some practitioners, especially at the technician level, will document the person whom they are conducting exposure monitoring on, and they don’t capture the detail of what that person is doing. They don’t paint the picture of that person’s exposure, nor do they look at other people with similar exposures. And sometimes it’s hard to ascertain who has a similar exposure in an operation, so they just don’t do it. JM: I think it comes back to the fact that a minority of the profession is following the AIHA strategy, which really pushes us to understand, document, and manage all the exposures to which workers are exposed during their workday. And if you’re not doing that, you’re not thinking very hard about how to do it efficiently and effectively. Now, once you decide that your job is to understand and manage all worker exposures, then you’re looking for ways to do that efficiently and effectively, and you have to do it by grouping people. You just cannot run around and measure exposures person by person by person. You have to think about how to group them in order to scale your approach. And that’s where SEGs are extremely helpful. MT: I think of the military as a prime example of an organization that is effectively documenting their SEGs. They have a handle on what people are doing and where and how. TS: What does the survey tell us about practitioners’ selection and use of OELs? JM: Many practitioners continue to prioritize the use of regulatory OELs over authoritative OELs, such as the ACGIH TLVs, despite the significant lag time that can exist before regulatory OELs align with current science. OSHA even recognizes that many of their PELs may be outdated and that the use of more recent authoritative OELs may be more appropriate. The good news is that 48 percent of respondents say they use the lowest available OEL, whether it’s a regulatory limit or an authoritative limit. TS: The survey captured some differences in the practices of corporate IHs versus those who work as consultants. What do you make of these differences? JM: I worked in the corporate world for many years, and I would say, generally speaking, people working in the corporate world have taken a more comprehensive approach than the small and medium-sized operations that do not have internal industrial hygiene expertise. And as you take on that comprehensive approach, you start to think more systematically about the fact that our PELs are really old, and it’s hard to argue that they’ve kept up with changes in the understanding of toxicology or how to set OELs. Because you are embedded in the organization, you’re able to learn the best ways to convince people to use a more proactive approach and use the authoritative exposure limits that have, in general, advanced with toxicology and OEL-setting practices much more quickly than regulatory OELs. I think for small and medium-sized enterprises, they don’t have internal experts to understand the technical reasons for adhering to the authoritative OELs and identify effective leverage points for their adoption. Because they commonly work with small and medium-sized organizations, we need to give practitioners working as consultants the tools and the language to explain the risks of adhering only to regulatory OELs so that they’re able to more effectively advocate for the use of authoritative OELs. MT: I have thirty-five years as a consultant, from being embedded as a program manager within large organizations to conducting one-off exposure assessment or exposure monitoring. A lot of the time, an entity either has had an OSHA inspection or they are afraid of an OSHA inspection, and they want to make sure that they’re in compliance. And that’s the bottom line for those entities. The larger clients that I had, like big defense contractors, certainly adopted and used the AIHA exposure assessment strategy. So, there’s a whole range of activities a consultant may be called in to address. When we would do monitoring reports, we always presented what the regulatory standard was and what the authoritative OELs were. When you make recommendations to a company, there’s two ways to do it. One is in writing, where it’s on the record that now they are aware of authoritative OELs and they can have some incentive to adopt the more protective standards. But then you have a lot of dialogue that’s off the record where you can help your client understand what they should be doing to better protect worker health. TS: Nearly half of survey respondents (45 percent) say they have an ad hoc approach to moving up the hierarchy of controls. What does a systematic process for moving up the hierarchy look like? JM: A systematic process would be clearly defined, documented, and followed. In addition to roles, responsibilities, and timelines, it would include the identification of opportunities to improve controls, a mechanism for prioritizing those opportunities, and the execution of an improvement plan in a traditional plan-do-check-act fashion. Prioritization criteria would include the potential exposure intensity and duration, the robustness of the current controls, the number of people potentially exposed, and the relative ease with which improved controls could be implemented. The time-cycle of the process would be set up in a way that can accommodate continuous improvements over time and the long lead times often needed to make the major changes necessary to implement controls at the top of the hierarchy. MT: I think many of us are reactionary in our approach to how we get things done in our businesses. What’s the current crisis or current modification that has to happen in order to get a process or production going, or get insurance, or get financing? There’s always something that you’re responding to, and I think that makes it difficult to have a systematic approach to moving up the hierarchy of controls, especially in smaller practices where you’re resource constrained. JM: I think that’s great insight generally. I don’t know of any OEHS professional who has any extra time. They’re always running behind because there’s too much to do and they have a really important role in keeping that operation up and running and safe. The treadmill is never ending. So, we have to give ourselves permission to let some things fall that feel really important, so that the proactive things can be put in place—to say, “Okay, we might be a month late on the annual hazard communication training, but during that month if we can put in place this proactive system for moving up the hierarchy of controls, in the long run the employees are going to be better off.”
“We have to give ourselves permission to let some things fall that feel really important, so that the proactive things can be put in place.”
TS: What have we learned from the survey about the differences between international practitioners and those based in the U.S.?
JM: We need to be careful about drawing conclusions, as my guess is that the international practitioners who responded to the survey are among the more sophisticated practitioners. In any event, the survey results indicate that international respondents are more likely to systematically define SEGs for all potential exposures, routinely use statistics, and have a systematic planning process for advancing up the hierarchy of controls.
I think part of it is there are regulations, in Europe in particular, that drive people to be more systematic about risk assessment. Basically, you as an employer have responsibility for systematically understanding your risks. Now, in general, those approaches are less detailed than the AIHA strategy, but they press people to put in place some kind of approach, so as a result, there is at least some systematic thinking about the risks that an employee might experience. And there is much more specific guidance about the use of statistics and the interpretation of monitoring results in other countries. OSHA has a lot of barriers to setting standards that require these kinds of comprehensive and proactive approaches, so we don’t see as many of them here in the U.S.
TS: A substantial number of survey respondents seem confused about statistical tools for exposure judgments. What do the survey findings say about this?
JM: The survey results indicate that we are not yet fully aware of the power that modern Bayesian statistical analysis tools provide. Seventy percent say that a barrier to using statistics is not enough measurements, yet Bayesian statistical tools have the ability to analyze datasets with sample sizes as low as 1. Twenty-eight percent say their measurements are too censored to use statistics, that too many of their sample results are less than the limit of detection. This indicates that many of us are still unaware of the elegant way Bayesian statistical tools can be used to analyze datasets that are highly censored, including those where every sample result is less than the limit of detection. And 34 percent say lack of training on Bayesian statistical tools is a barrier to their exposure assessment processes, apparently unaware of the wonderful free online training offered by AIHA. [Editor’s note: The free online course “Making Accurate Exposure Risk Decisions” is available from AIHA's website.]
MT: It’s still surprising to me that people say they don’t have enough data to analyze. The beauty of the Bayesian statistical tools is that you can perform quality statistical analysis with very few data points to judge your exposures. It just defies logic that people still think they need these giant datasets. I think people are generally afraid of statistics.
JM: I think that’s true, and I think that rather than digging in and learning and taking advantage of the free training and tools that AIHA is offering, people are finding excuses about why the statistics won’t work. If we are hesitant to use statistics because we have few monitoring results or we have a lot of results below the limit of detection, then how are we able to make a good decision just using our intuition, without any systematic tools? So, it just reinforces the concern that our profession is not using the tools, and underestimating exposures as a result. We become overconfident even though we understand the basic limitations of having few samples or many sample results below the detection limit.
MT: I also think that we’re really good in terms of thinking about the bell curve, but we’re poorly adapted to thinking in terms of a lognormal distribution. And until you really look at the tools that we have, you can’t gain an appreciation for how much variability could be in your dataset. So, it’s a challenge. We’ve got to unlearn something that we’ve relied on forever and learn a new way of thinking.
JM: Michele makes a great point. We understand intuitively that variability is important, but our base experience as humans makes us want to use the symmetrical bell-shaped normal distribution instead of the skewed-to-the-high-end lognormal distribution that’s more appropriate. And if we’re not using these statistical tools, we’re unable to intuitively picture what’s happening in those few periods of high exposures that are important to us as we think about conformance with OELs.
TS: What are the main barriers to adoption of best practices in OEHS, and how do we overcome them?
JM: Lack of support for the training, time, and expense associated with best practices are the most often cited barriers. Around one-third of respondents indicated lack of training on Bayesian statistical analysis, lack of support and resources from management or decisionmakers, and lack of time to complete documentation as major barriers.
To overcome those barriers, we need to ensure that practitioners fully understand the best practices and the advantages they provide, not just in terms of more effective worker protection, but in terms of increased program efficiency as well. We have numerous examples of cases where the implementation of AIHA’s exposure assessment strategy not only increased the effectiveness of exposure management efforts, but increased efficiency too. The approach ensures that the resources spent on things like exposure measurement and control are being spent in a way that is most effective.
“Until you really look at the tools that we have, you can’t gain an appreciation for how much variability could be in your dataset.”
And we need to teach practitioners how to frame and sell the need for these critical practices to the people who hold the purse strings. We’ve got to learn to explain the value of these approaches to clients in a way that is relevant to them. We think that laying out the dollars and cents will make the difference for people. What we forget is that the pressures of the day are weighing on these folks. The people in operations who hold the purse strings are bombarded all the time about, “You need to get it out faster, you need to get it out cheaper, you need to get it out safely.” And the logic of “You can save X dollars a month by doing it this way as opposed to that way” is competing with lots of other pressures and opportunities, many of which have much higher return than some of the things that we’re able to show.
What we need to teach each other is how to leverage not only the scientific and economic aspects but the human aspects as well—how to start framing things in the common human language of caring for each other and caring for our fellow humans. We need to teach OEHS practitioners how to create a calm and safe place where those kinds of conversations can happen. You can’t do it in the heat of, “Oh my gosh, we’re out of conformance with this OEL, we need to do something fast.” You have to have those conversations in a place where people can remember that we’re talking about our fellow humans, that we really don’t want to hurt them—nobody wants to hurt the folks they work with. And so we want to frame things in a way that goes beyond compliance and return on investment, to talk about, “You know, our workers are exposed to some significant risks, those risks are unacceptable, here’s why we think they’re unacceptable, and here are some options for moving forward. We can implement this short-term fix, and in the longer term we’re going to move forward with our systematic approach to further understanding the exposure issues and moving up the hierarchy of controls.”
And when you start to be systematic in your approach, you have to form partnerships with people in engineering and people in manufacturing so they know what you’re doing and how they need to engage with you. The people who hold the purse strings understand that kind of engagement. They appreciate systematic, process-based, continuously improving approaches.
MT: Making that business case has always been a challenge for people in our profession. We’re one of many stakeholders that a facility manager has to deal with. And if we can’t speak the language that they understand, then whatever we’re sending out there cannot be received. So communication’s definitely key. We tend to be the smartest people in the room, in our humble opinion, and we lose sight sometimes of how we fit into the bigger picture.
JM: I think because we’re coming in as experts, we tend to lead with one answer, like “Eliminate it. This is bad; eliminate it.” And we forget that the folks who we’re talking to have many, many stakeholders. Very often, “eliminate it” is a really complicated process. We’re better off recognizing that there are many things the purse-string holders have to conform to, and instead bring a clear step-by-step roadmap with options of how we’re going to move forward, in both the short term and the long term.
MT: It goes back to continuous improvement. It’s not meant to be done overnight—it can’t be done overnight. But over time, you’ll get there.
TS: Was there anything more you wanted to say about the survey?
MT: Just that there’s so much rich content that we haven’t even begun to scratch the surface. We picked the cream off the top—we didn’t even get into more granular analysis yet. There’s plenty more that we can mine out of this data.
JOHN MULHAUSEN, PhD, CIH, CSP, FAIHA, retired in 2018 from 3M where he worked for 31 years in a variety of global health and safety risk management roles, most recently as director of corporate safety and industrial hygiene.
MICHELE TWILLEY, DrPH, CIH, is AIHA’s staff industrial hygienist.
ED RUTKOWSKI is editor-in-chief of The Synergist.
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AIHA: A Strategy for Managing and Assessing Occupational Exposures, 4th ed. (2015).
AIHA: “Making Accurate Exposure Risk Decisions.”
AIHA: “New Initiatives Aimed at Advancing OEHS Science and Practice.”