Recent discoveries of carbon-free helium deposits in Tanzania and Minnesota have encouraged scientists to develop methods of detecting other similar reservoirs around the world. A new study analyzes the conditions of three geothermic areas around the world—including Yellowstone in the U.S.—to develop methods for detecting where these precious sources of helium may accumulate. In fact, the element was so important that the U.S. had a strategic helium reserve for decades (though the government sold off that reserve just last year). However, in recent years, scientists have found some evidence that caches of helium free from fossil fuels do exist. The most notable recent examples of this include when scientists discovered a massive underground helium reserve in 2016 in Tanzania, and when they uncovered an additional helium deposit in Minnesota in 2024.