Bear spray is exploding in the trash near Yellowstone National Park

May 14-Every day, workers at a garbage transfer station near Yellowstone National Park clock in with a troubling question on their minds. Will today be the day we inhale a freshly exploded can of bear spray?

Garbage from Yellowstone gateway communities, such as Gardiner and Cooke City, is collected throughout Park County in Montana before it ends up at the transfer station. Here, in this rugged and rural area, around 18,000 locals and millions of tourists are encouraged to carry bear spray - cans of high-powered, long-distance pepper spray meant to deter a charging bear - when they're hiking, biking or exploring the woods. Bear spray costs roughly $40 a can, and it works by temporarily blinding bears and causing them to choke and cough, stopping a charge before it can result in injury or death.

But at the end of a trip to Yellowstone, visitors who bought bear spray as a precaution find themselves with a problem. Bear spray, a flammable aerosol, isn't allowed on airplanes. And for travelers who drove, the spray likely isn't necessary back home. Many people don't quite know what to do with it: So, they throw it away.

An unknown number of bear spray cans end up in the trash throughout the county's collection sites. And then, roughly once a month, they explode. The latest explosion occurred in mid-April during the trash compaction process.

"We fairly frequently pop open a can of bear spray, which then spreads throughout the entire transfer station, forcing my guys to try to get out of the building as quickly as they can," said Matt Whitman, the director of the Park County Public Works Department.

Sanitation employees there are usually working in equipment with a cab, "so they don't immediately get a face full of mace," Whitman added. But capsicum spray designed to bring down a lumbering bear is so high-powered that it leaves workers tearing up and coughing. "We definitely have had staff that get it enough that their eyes are watering and they're irritated for the rest of the day," he said.

Explosions delay the crews' work for one to two hours while fans clear the air. "You can see the mist in the air, and you start smelling it through the vents," Whitman said. "It's completely unpleasant."

Whitman said he's seen the problem increase in the last six years, in step with the national park's skyrocketing visitation. According to park data, Yellowstone saw 3.8 million visitors in 2020 and around 4.8 million visitors in 2025.

"We're all doing this good thing by carrying bear spray," said Evan Stout, the owner and operator of the Yellowstone Wildlife Guide Company and the program coordinator for Bear Awareness Gardiner. "But there's no end game for those cans."

The effective lifespan of bear spray compounds the problem of can disposal for locals. Bear spray expires in three to five years when the can loses pressure, limiting how far the spray can reach and how effective it is. Experts say you should replace bear spray after the expiration date printed on the can.

But there aren't good options to safely dispose of bear spray, expired or not, around Yellowstone. The national park doesn't collect or recycle bear spray canisters, according to a spokesperson.

Yellowstone Forever, the park's fundraising arm, and Counter Assault, a bear spray manufacturer, used to collaborate on a recycling program that included drop boxes in nearby Bozeman, Montana, and elsewhere. The program began in 2011 and existed through at least 2016. Funded by Counter Assault, it entailed filtering out the spray ingredients before puncturing, flattening and selling aluminum to recycling centers.

Counter Assault did not respond to questions about when the recycling program ended or why. The company's website still references recycling programs that no longer exist and encourages customers to contact their local waste management company or recycling center. Whitman said that to his knowledge, there aren't operable bear spray recycling units in the Greater Yellowstone area today.

Another bear spray manufacturer, UDAP, once accepted used canisters at its facility in Butte, Montana, for recycling. UDAP did not respond to questions about when or why this recycling program ended. The company now encourages people to "move to an open area away from people, pets, and buildings," spray the container, and dispose of it in the trash. "Be sure to stand upwind in a well ventilated area when doing this so you won't harm yourself or others in the process. This practice is a great way to train yourself and others how to use the spray," the website reads.

Rental companies are starting to offer travelers more options. People can rent and then return bear spray instead of throwing it away. Several companies offer rental services in the Yellowstone area, including TrailQuipt, Bear Spray Shack and Bear Aware.

Meanwhile, the Park County Public Works Department is installing six bear spray-specific collection containers where people can drop off their spray and keep it separate from the rest of the trash. They still don't have a place to take them afterward, but Whitman hopes fewer cans will end up in the compactor as a result. He envisions potentially collecting cans for several years until a better disposal option exists.

"If my guys aren't getting maced every month or two, that's still a better result than it going in the garbage," Whitman said. "I'd like to think that once people have the option, that they'll be more responsible."

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