On July 18, 2024, an accident involving children and a broken thermometer in a Daly City residential apartment caused a mercury release onto carpet. The thermometer was an old international model and contained an unknown amount of mercury. In an effort to clean up the mercury, the homeowner ran the vacuum over the release. This should never be done with a regular vacuum, because it spreads the contaminant throughout the home. An infant and toddler occupy the residence with their parents so the family self evacuated to ensure there was not a health threat. San Mateo County conducted an initial assessment of the apartment and it's air quality and determined the mercury detections were high enough to warrant further assessment and a cleanup before the residents should return. They requested EPA assistance on July 19, 2024. EPA deployed with contractors to conduct a further assessment and begin cleanup in coordination with the apartment managers on July 20, 2024.
Any amount of mercury spilled indoors can be hazardous. The more mercury is spilled, the more its vapor will build up in air and the more hazardous it will be. Even a small spill, such as this one from a broken thermometer, can produce hazardous amounts of vapor if a room is small enough, warm enough and people spend a good deal of time there, as in a small bedroom. Mercury can break into droplets when spilled and the droplets spread easily and can build up in tiny cracks and spaces in your house. Mercury can vaporize (evaporate) into the air in your house. The vapor cannot be seen or smelled. Mercury can be toxic to people’s nervous system, lungs and kidneys.
The following groups of people are particularly sensitive to the harmful effects of mercury:
Pregnant women - Mercury can pass from a mother’s body to her developing fetus.
Infants - Mercury can also be passed to nursing infants through breast milk.
Young children - They tend to play on floors where mercury may have been spilled, and are more likely to breathe more vapors than an adult because they breathe faster and have smaller lungs.
