Hydrogen sulfide poisonings in hot-spring reservoir cleaning: two case reports

The potential hazards to maintenance personnel cleaning hot-spring reservoirs are reported following two severe and unusual episodes of acute hydrogen sulfide poisoning involving seven workers. In the first episode, five victims lost consciousness immediately after climbing down a manhole to the bottom of a reservoir disregarding a strong odor of rotten eggs. One of them died immediately. Of the four who lived, three developed hemorrhagic keratoconjunctivitis and aspiration pneumonia, but no sequelae were observed 2 years later. In the second episode, two workers had been cleaning the reservoir for about 2 hours when one collapsed and his companion went to seek help. Both died of acute respiratory distress syndrome due to pulmonary edema within 12 hours. Since hot-spring bathing is a popular recreation in Taiwan, other accidents of hydrogen sulfide poisoning may have occurred but have not been reported. Such clinical information is helpful to enable regulators to initiate proper precautions to safeguard those workers involved.