May 26, 2023

Upsetting the IH Paradigm

By Ed Rutkowski

Question everything: this seemed to be the motivation behind a provocative session held Tuesday at AIHce EXP 2023 during which presenters Steve Jahn, Phil Smith, and Mike Phibbs encouraged their audience to reimagine the very foundations of modern industrial hygiene. They argued for a new understanding of the term “sample.” They suggested minimizing IHs’ reliance on similar exposure groups (SEGs) and time-weighted averages (TWAs). They even proposed shaking up the IH process of anticipate, recognize, evaluate, control, and confirm (ARECC) by shifting “control” to a new spot in the order (ARCEC).

Smith opened with a brief history of sampling. The 1950s and 1960s saw the widespread adoption of constant-flow pumps and laboratory analytical methods such as gas chromatography and atomic absorption and emission spectroscopy. In the United States, the 1970 Occupational Safety and Health Act legislated the expectation that employees would be protected through the measurement of exposures—specifically, TWA chemical concentrations for comparison against occupational exposure limits. Laboratories’ focus on quality ensured that their reports characterized samples with a high degree of precision.

Due to the expense of sampling, best practice dictated the division of workers into SEGs. The assumption behind SEGs is that statistical analysis of a few samples could provide enough information about exposures to protect large numbers of workers. The drawbacks of this approach were apparent from the start. Smith quoted a 1977 NIOSH publication that described SEGs as “an undesirable compromise” necessitated by “limited numbers of industrial hygienists and few resources available to measure the exposure of each employee.” In essence, Smith said, we know that SEGs may not represent exposures to all members of a group; we use SEGs because we can’t collect enough samples.

But with the advent of real-time monitors, IHs can collect many more samples much more quickly, provided we broaden our understanding of what a “sample” is. That same 1977 NIOSH publication defines a sample as “airborne contaminant(s) collected on a physical device,” a definition that is baked into regulations, ensuring that tubes and pumps are needed for compliance—even though real-time monitors showed that these tools miss a great deal of variability in exposures. Pumps are designed to help IHs determine the TWA, but if you look only at an average concentration, you miss spikes in exposures that happen over the course of a workday or work shift.

While real-time personal monitors don’t provide the same accuracy as traditional samplers, they are accurate enough to inform health-protective interventions. In any case, Smith argued, the ability to monitor exposures across the entire worker population and address day-to-day exposure variability is worth small compromises in accuracy and precision.

IHs need to “escape the bounds of the traditional sample,” Smith said, to fully realize the potential of real-time monitors and developments such as the Internet of Things, the network of physical objects with sensors that exchange data.

The remainder of the session provided additional context for the themes Smith introduced. Phibbs discussed his successes with control banding, a qualitative approach to identifying control methods, especially when working with small employers that can’t afford IHs. Control banding is not new, but some IHs have been reluctant to adopt it, presumably due to a preference for precisely measuring exposures through sampling and using those data to determine controls. Phibbs seemed to suggest that waiting for sampling data wasn’t necessary in many contexts and that there should be more urgency to control exposures—advocating, in effect, for the “control” step of ARECC to move up in the process.

The success of control banding in small businesses yields important insights for the future of the profession, according to Jahn. “There’s an awful lot of employees who don’t have any of us watching out for them, and we have to figure out a simpler way of doing business,” he said. “Nobody’s going to have the money to hire one of us to come in with a sampler.”

Ed Rutkowski is editor in chief of The Synergist.

For Further Reading

The Synergist: “The Challenge for Industrial Hygiene 4.0: A NIOSH Perspective on Direct-Reading Methodologies and Real-Time Monitoring in Occupational Environments” (February 2022).