Miasma
A woman and her two children have died at a hot spring resort, likely from inhaling noxious gas:
On 29 December, University of Tokyo tutor Yasushi Matsui (47) of Toshima Ward, Tokyo, was in critical condition and his wife and two sons died at the Doroyu Hot Springs in Yuzawa City, Akita Prefecture; on 30 December, the Yuzawa Station of the Akita Prefectural Police began an investigation into the circumstances of the accident near the Okuyama Inn, where the four were found collapsed close to a snow-covered basin [as in a depression in the ground, not as in a birdbath–SRK].
The Yuzawa Station considers it possible that the family of four inhaled
sulfur oxidehydrogen sulfide [Bad transation my fault, sorry; the article did, indeed, say 硫化水素.–SRK] gas that had accumulated in the basin and been poisoned; it is hurrying to establish the cause of death through autopsies of the dead woman and boys.According to the investigation, the basin has a diameter of 2 meters and a depth of 1.5 meters; it is located about 10 meters from one side of the inn’s parking lot.
I’ve somehow never managed to get to Yellowstone, but I’m assuming toxic gases are a problem at some of its fumaroles and things, too. In Japan when you go to see steam vents and the like in hot spring areas, there are often purposefully scary signs posted that warn you to leave the area immediately if you start feeling funny. They also warn that people with heart conditions and the like should stay away. Unfortunately, the ground has lots of cracks, some small and unnoticeable.
Hydrogen sulfide is nasty stuff. I spent several months as a safety man at a sour gas refinery in northern Canada during my wayward youth. The most evil thing about it is that in lethal concentrations, you can’t smell it. We lost two guys during my time, climbing into tanks without a complete nitrogen/air flush.
Yeah, I did that thing where I read too quickly, and my brain put it in English word order, which came out something that would have been nonsense like “sulfur monohydride,” and I apparently grabbed for the nearest realistic option.
But hydrogen sulfide is…well, it’s hydrosulfuric acid, isn’t it? What I don’t remember about chemistry could fill my 10th grade textbook, but is HS colorless/odorless/tasteless?
Oh, yeah, it stinks…but if you can smell it, you’re safe. The nasty bit is that when it reaches lethal concentrations, it “jams” your sense of smell and you don’t notice it.