Staff at the Yellowstone Volcano Observatory have been conducting frequent cleanups of the park’s hydrothermal areas, retrieving a growing number of items discarded or accidentally lost near hot springs, geysers, mudpots, and fumaroles. The effort, ongoing from January through September 2026, has resulted in a record haul of over 20,000 pieces of trash, along with thousands of rocks, sticks, and hundreds of hats.

Yellowstone’s geology team, trained to operate safely around hazardous geothermal features, carries out these cleanups several times per week using specialized tools such as grabber poles and strainers. Their work extends beyond that of interpretive rangers, who are limited to boardwalks and established trails due to safety concerns.

“This year, we collected approximately 20,100 pieces of trash, including plastic bottles, tissues, candy wrappers, and personal items, compared to just over 13,000 pieces during the same period last year,” said Michael Poland, scientist-in-charge at Yellowstone Volcano Observatory. Rocks, sticks, and hats also saw significant increases.

Among the various objects recovered were common personal items like sunglasses, jewelry, camera lens caps, hotel key cards, pacifiers, and single AirPods. The team also found nearly $20 in U.S. and foreign currency, including pesos, yen, euros, and Canadian coins. Notably, the collection included six Invisalign retainers and 42 pencils, along with a diverse assortment of children’s toys, such as mini racecars, bouncy balls, rubber ducks, and action figures.

Poland suggested that many items are lost accidentally. Hats and sunglasses can be blown off by the wind, and small objects may be dropped or knocked into unsafe areas where visitors cannot retrieve them. However, some items, like rocks and coins, appear to have been deliberately tossed into hydrothermal features.

The accumulation of foreign materials poses a risk to Yellowstone’s geothermal features. Poland highlighted the example of Morning Glory Pool, a hot spring once known for its vibrant blue color. Visitor-thrown coins and debris over decades clogged the spring’s vents, lowering its temperature and altering its bacterial composition. Attempts to clean and restore the pool in the 1970s, including partial draining and vacuuming, have only partially reversed the damage.

Yellowstone’s geothermal experts use protective gear and carefully approach areas close to venting steam and hot water that are inaccessible to most visitors. After documenting the recovered items, unsalvageable trash is discarded, while reusable objects like hats and toys are cleaned and donated to local charities.

The collection efforts are also compiled and cataloged, with plans to create a detailed record of distinctive items found. This year’s notable finds include hats related to the FIFA 2026 men’s World Cup, a baseball cap labeled “COWBOY HAT,” and a Roblox bucket hat from Saint Kitts and Nevis.

Officials stress that park visitors should take care to secure their belongings and avoid dropping objects into thermal areas. Poland advised guests to “cinch your hat on tight” and secure loose items in pockets or backpacks, noting that even dental retainers have been found among the debris.

The cleanup initiative underscores ongoing challenges in preserving Yellowstone’s unique geothermal environment while encouraging responsible visitor behavior.