The U.S. Geological Survey took a break from giving serious updates about Hawaii’s Kilauea volcanic eruption to confirm that no, you should not roast marshmallows over the scorching hot volcanic vents. The USGS responded to one twitter user who asked, “Is it safe to roast marshmallows over volcanic vents? Assuming you had a long enough stick, that is? Or would the resulting marshmallows be poisonous?” The USGS replied. “We’re going to have to say no, that’s not safe. (Please don’t try!)” Not only would it be unsafe, the USGS said, but the marshmallows would simply taste bad. The vent could be releasing sulfur dioxide or hydrogen sulfide, which both emit not-so-pleasant smells.
Erm...we're going to have to say no, that's not safe. (Please don't try!) If the vent is emitting a lot of SO2 or H2S, they would taste BAD. And if you add sulfuric acid (in vog, for example) to sugar, you get a pretty spectacular reaction.— USGS Volcanoes🌋 (@USGSVolcanoes) May 29, 2018