Toxic Gas, Lifesaver; March 2010; Scientific American Magazine; by Rui Wang; 6 Page(s)
Imagine walking into a hospital emergency room, with its hand-sanitizer-adorned walls and every surface meticulously scrubbed free of contaminants, only to encounter the stench of rotten eggs. Distasteful though this juxtaposition might sound, the toxic gas synonymous with that smell—hydrogen sulfide (H2S)—may well become a fixture in such settings in the future. Over the past decade scientists have discovered that H2S is actually essential to a number of processes in the body, including controlling blood pressure and regulating metabolism. Our findings indicate that if harnessed properly, the gas could, among other benefits, help treat heart attack patients and keep trauma victims alive until they can undergo surgery or receive a blood transfusion.
A Whiff of Poison
Scholars have known about H2S's toxic effects on humans for centuries. Today it constitutes the number-one occupational safety hazard at oil and gas field wellheads, along pipelines, in processing plants and in refineries. Our noses can detect H2S at concentrations of 0.0047 part per million (ppm). At 500 ppm, it impairs breathing. Exposure to 800 ppm for five minutes leads to death. Yet, paradoxically, we need H2S to survive.