Divine Aleru is an accomplished biochemist and researcher with a specialized background in environmental toxicology, focusing on the impacts of heavy metals on human health. With deep-rooted expertise in microbiome signatures analysis, Divine seamlessly blends rigorous scientific training with her passion for deciphering the intricate relationships between environmental exposures and the human microbiome. Her career is distinguished by a commitment to advancing integrative health interventions, leveraging cutting-edge microbiome research to illuminate how toxic metals shape biological systems. Driven by curiosity and innovation, Divine is dedicated to translating complex environmental findings into actionable insights that improve individual and public health outcomes. 
Divine Aleru is an accomplished biochemist and researcher with a specialized background in environmental toxicology, focusing on the impacts of heavy metals on human health. With deep-rooted expertise in microbiome signatures analysis, Divine seamlessly blends rigorous scientific training with her passion for deciphering the intricate relationships between environmental exposures and the human microbiome. Her career is distinguished by a commitment to advancing integrative health interventions, leveraging cutting-edge microbiome research to illuminate how toxic metals shape biological systems. Driven by curiosity and innovation, Divine is dedicated to translating complex environmental findings into actionable insights that improve individual and public health outcomes. What was studied?
The study investigated occupational exposure to mercury at an electronics waste and lamp recycling facility in Ohio in 2023. The research focused on assessing elemental mercury exposure in workers through air sampling and urine mercury testing. The facility in question was involved in the recycling of mercury-containing lamps and electronics, where mercury vapor and dust are common occupational hazards. The study conducted by the CDC’s National Institute for Occupational Safety and Health (NIOSH) aimed to evaluate the levels of mercury vapor in various areas of the facility, the health status of workers, and whether the exposure levels exceeded established safety thresholds. The study also identified areas of concern within the facility’s ventilation system and recommended control measures to reduce mercury exposure risks.
Who was studied?
The study involved 15 workers at the recycling facility in Ohio. The workers were from various job functions, with a focus on those working directly in the lamp recycling areas where mercury exposure was most prevalent. The study included a mix of workers with varying tenures, some of whom were non-English speakers, which highlighted potential barriers in understanding safety protocols and using personal protective equipment (PPE). The workers participated in interviews to assess work history, symptoms consistent with mercury toxicity, and medical and social factors. Additionally, spot urine tests were collected from the workers to measure inorganic and elemental mercury levels, and environmental air samples were taken to evaluate mercury vapor exposure throughout the facility. Six workers in the lamp recycling areas had elevated mercury levels in their urine, with some reporting symptoms such as metallic taste, difficulty thinking, and personality changes, indicative of mercury toxicity.
Most important findings
The investigation found that mercury vapor was present in all sampled areas of the facility, with elevated concentrations in both production and non-production areas. In the lamp recycling areas, mercury vapor concentrations exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) in many instances, with levels as high as 106.3 µg/m³, surpassing both the NIOSH recommended exposure limit (REL) and the OSHA permissible exposure limit (PEL). This indicated that the facility’s ventilation system was insufficient to protect workers from harmful mercury vapor levels.
Urine mercury testing revealed that six of the 14 workers tested had elevated mercury levels above the ACGIH biologic exposure index (BEI), which is 20 µg/g creatinine. Notably, workers in the lamp recycling areas had higher mercury levels than those in other areas, with a median mercury-to-creatinine ratio of 41.3 µg/g. Symptoms of mercury toxicity, including metallic taste, cognitive difficulties, and changes in personality, were reported by workers with elevated mercury levels. These findings suggest that long-term exposure to mercury vapor and dust in the facility posed a significant health risk to workers, particularly in the lamp recycling areas.
Key implications
For the Heavy Metal Tested and Certified (HTMC) program, this study provides critical insights into the risks of occupational mercury exposure, especially in recycling facilities. The findings emphasize the need for HTMC guidelines to include stringent monitoring and control measures for mercury exposure in facilities where it is a risk, such as electronics and lamp recycling centers. HTMC standards should incorporate the use of effective ventilation systems, regular mercury vapor testing, and the proper use of PPE to minimize worker exposure. Additionally, HTMC certification can encourage recycling facilities to adopt safety protocols that include worker training in multiple languages, especially in settings where language barriers exist, to ensure proper use of protective gear and understanding of the risks involved.
Citation
Shi, D. S., Charles, M., Beaucham, C., Walker, S., Alarcon, W., Brueck, S. E., Chiu, S. K., & Somerville, N. (2025). Occupational Exposure to Mercury at an Electronics Waste and Lamp Recycling Facility — Ohio, 2023. Morbidity and Mortality Weekly Report, 74(1), 9. https://doi.org/10.15585/mmwr.mm7401a2
Mercury (Hg) is a neurotoxic heavy metal found in various consumer products and environmental sources, making it a major public health concern. Its regulation is critical to protect vulnerable populations from long-term health effects, such as neurological impairment and cardiovascular disease. The HMTC program ensures that products meet the highest standards for mercury safety.
