Mercury vapour levels in a domestic environment following breakage of a clinical thermometer.

Following the breakage of a clinical thermometer in the kitchen of the author's own home, mercury vapour was found to be present in most rooms, but not in concentrations which exceeded the current threshold limit value (TLV). However, assuming a more stringent standard of safety, based on continuous exposure to mercury vapour, it was noted that some of the readings could be considered to be excessive, although these were of a freakish and transient nature. In reality the overall time-weighted average exposure of the occupants was within reasonable limits. Lack of ventilation was a major factor in maintaining discernible levels of vapour over a 3-week period. However, the advent of mild weather was instrumental in dispersing the vapour, by allowing the opening of windows. The residual mercury on the floors would seem to have evaporated, so that no long-term health risk ensued. Cross contamination of the hallway carpet was noted indicating that mercury had been transported on the soles of feet and shoes.