An “Emerging Interest”: Occupational Exposure to OPEs
By Ed Rutkowski
NEW ORLEANS, Louisiana (June 2, 2026)—A recent Canadian study suggests that occupational exposure to organophosphate esters (OPEs), a class of chemicals used as plasticizers and flame retardants, is widespread among paramedics, firefighters, and office workers. At AIHA Connect 2026, Victoria Arrandale, a professor in the University of Toronto’s Dalla Lana School of Public Health, presented results from the study and characterized OPEs as “an occupational exposure of emerging interest.”
Arrandale explained that the use of OPEs as flame retardants has become more common in recent years. Flame retardants are often incorporated into consumer products to meet flammability standards. Driven by restrictions on polybrominated diphenyl ethers, another class of chemical flame retardants that has been linked to developmental effects in children, manufacturers have replaced PBDEs with OPEs. OPEs are now present in furniture, electronics, insulation, and many other consumer goods. Like PBDEs before them, OPEs are typically mixed into materials. Because they are not chemically bound, the chemicals are released over time into air and dust, leading to potential human exposures.
“OPEs have been quantified in almost everything,” Arrandale said, including air, water, and food. They are present in both indoor and outdoor environments. Animal studies suggest that the health concerns of exposure to OPEs range from hormonal disruption to dysregulated thyroid and include potential reproductive effects and, possibly, cancer. This year, the International Agency for Research on Cancer characterized the chemical TCPP, an OPE, as “probably carcinogenic.” IARC had found a different OPE, the chemical TCEP, to be “not classifiable as to its carcinogenicity to humans” in 1998.
The study Arrandale presented was largely the work of doctoral student Fateme Kooshki, who was unable to attend AIHA Connect. For 24 hours, study participants from three occupational groups—paramedics, firefighters, and office workers—wore silicone wristbands that absorbed chemicals. Participants also provided urine samples and completed a short questionnaire. The wristbands were analyzed for 13 OPEs and the urine samples for metabolites of 12 OPEs.
Analysis showed that the most abundant OPE was triphenyl phosphate (TPHP). Levels of TPHP were higher on wristbands worn by firefighters and paramedics than by office workers, Arrandale said. For most analytes, paramedics had the highest accumulation of OPEs on their wristbands, a result that surprised researchers, who had expected to find evidence for greater OPE exposures among firefighters.
That was the case with the urine samples, which showed higher concentrations of OPE metabolites for firefighters than for the other groups. Still, the results were less pronounced than expected, with “surprisingly high” levels of OPE metabolites in the paramedics’ samples, Arrandale said.
The researchers also sought to determine whether a relationship existed between exposures quantified from wristbands and those quantified from urine. A positive correlation would mean that future studies could potentially use wristbands alone to characterize exposures, eliminating the need to ask participants to provide urine samples. For most of the OPEs studied, Arrandale said, “the correlation was positive, but very weakly so,” meaning that wristbands are probably not sufficient to capture total exposure.
Arrandale cautioned that the study was small—participants included 12 paramedics, 40 firefighters, and 13 office workers. Still, the results showed higher OPEs among these groups than in the general population, suggesting that workplaces are adding to exposures.
The study was published in the April 2026 issue of Annals of Work Exposures and Health.
Ed Rutkowski is editor-in-chief of The Synergist.