On May 20, 2025, the Missouri Department of Natural Resources requested federal assistance with a mercury release within a residence in Saint Louis, Missouri. EPA deployed to the scene the same day and conducted an assessment of the release and confirmed the presence of elemental mercury and mercury vapors in the residence.
According to the resident, a full, 16-ounce mason jar of elemental mercury broke and spilled inside the upstairs unit at the residence on May 6, 2025. Over the next few days, the tenant attempted to recover and dispose of the mercury in an alley recycling dumpster behind the residence.
The initial assessment determined that vapor concentrations are present in the home at levels that exceed the residential removal action goal for indoor air. This presents a health risk to the residents of the home. Furthermore, while the spread of mercury contamination appears to be limited, the continued presence of elemental mercury contamination in the upstairs unit could result in additional cross contamination by future residential activities.
The EPA initiated a emergency removal action on May 21, 2025. This Emergency Removal Action will address the
release of elemental mercury at the residence that is causing mercury vapor concentrations to exceed
the residential removal goal for indoor air.
Removal response actions have included the bagging, removal, and assessment of personal belongings and bulk items from the second-floor apartment, assessment and removal of elemental mercury, ventilation of the building, removal of wooden flooring, regular screening of mercury vapor concentrations throughout the apartment on all floors with mercury vapor analyzers, and sealing the subsurface in areas where flooring was removed.
