In a bit of citizen science, IndyStar conducted an experiment to test a claim that the balloons released by the Indianapolis Motor Speedway each year are biodegradable, and therefore pose little risk to wildlife.

And the results? Eleven months later, some of the balloons tested did degrade, but they still would pose a substantial risk.

IMS has released balloons on race day since the 1940s, one of many organizations to commemorate special occasions with the colorful spectacle. But in the decades since, awareness about the environmental damage caused by balloons, and other litter, has made many people rethink the practice.

Even the Balloon Council, which represents the industry, changed its stance on balloon releases last year from neutral to opposed. The group now recommends that balloons be weighted or tied down, and then popped and disposed of after they're used.

IMS spokesman Alex Damron did not provide a comment for this story. In April, he told IndyStar that the balloon release would remain part of Indianapolis 500 tradition, but that IMS was evaluating feedback on the issue.

"We’re reaching out to several stakeholders and talking with experts to fully understand the impact of this practice and determine its status in the years ahead,” he said at the time.

Our experiment

On Sunday, as race fans listen to “Back Home Again in Indiana,” IMS plans to release several thousand balloons into the atmosphere again this year.

Ahead of the balloon release last year, IndyStar received complaints and Damron defended the tradition, highlighting its use of balloons that are “are 100 percent biodegradable" and made from natural rubber latex.

IndyStar decided to conduct the experiment after criticism continued. Damron did not confirm what brand of balloons IMS uses, but an IndyStar file photo from 2017 shows BSA Balloons, which are made of natural rubber latex.

Using that brand, IndyStar submerged two balloons into fresh water and two into salt water. Two more were placed in a pot of soil, and the final two were put in a compost pile in Hendricks County.

That’s where the balloons remained from June 29 until Tuesday.

The results: While some of the balloons did show some deterioration, most of them remained largely intact after nearly 11 months.

Three balloon release controversies:You should know about

All of the balloons submerged in water looked and felt nearly identical to balloons right out of the package.

The final pair of balloons – the pair exposed to the actual elements – fared much worse. The one that was under the compost pile is much more brittle and less elastic than the unexposed balloons.

But all of the balloons were still well enough preserved to pose the types of risks feared by wildlife officials.

What the experts have to say

Critics say the discarded balloons can pose a danger to wildlife and marine species in the time it takes them to break down — which can amount to years.

Emma Nelson, a biologist from the U.S. Fish and Wildlife Service, said that some species, including sea turtles, mistake debris from balloons and plastic bags for food. The animals either suffocate to death or starve with a belly full of plastic.

Even though Indiana is virtually landlocked, Nelson said, the balloons released here can find their way to the ocean.

"The distance is kind of incredible, that our waterways can move things," Nelson said.

Katie Register, a executive director at Clean Virginia Waterways at Longwood University, was not surprised to hear that the balloon in the compost pile was the most degraded. That’s where the material would have been much more exposed to bacteria.

In August, Register and her colleagues published a paper about balloon litter on Virginia's remote beaches. They found more than 11,400 balloons, balloon pieces and attachments in a five-year period, making it the most common debris found along those beaches.

Globally, about 80% of marine debris is made of plastics, but experts still view balloon litter as a serious threat to wildlife — and one that is easy to avoid.

"Whether something is biodegradable or not, we have to stop littering," Register said. "And balloon releases are balloon littering events."

According to the study, balloons found along Virginia beaches may have been released as many as 1,400 miles away, based on the graphics printed on the balloons.

Register also researched some of the social motivations behind balloon releases. Based on media reports, she found that 58% of balloon releases are coordinated for memorial events.

Changing opinion on balloon releases

Opinion concerning balloon releases has changed over time, said Lorna O’Hara, executive director of the Balloon Council.

That’s why, in August, the Balloon Council announced that it was changing its position on balloon releases to discourage the practice. Previously, the organization had been neither for nor against releases of latex balloons, but offered best practices to limit their harm. The group has always been against releasing foil balloons.

"The education has been effective throughout the years. We just shifted with the time and temperament of society," O'Hara said.

Several states and cities across the country have moved to ban balloon releases or otherwise regulate the way balloons can be distributed. At least eight states considered this year some type of legislation that would limit balloon releases, according to the Associated Press.

O'Hara said that her organization is not opposed to banning balloon releases, but is ready to step in where there is particularly "erroneous language," she said.

“We want to make sure that there are balloons around in the future,” O’Hara said. “It would be a shame because of people’s behavior that the enjoyment of balloons would go away completely. The balloon is not the culprit, it’s the people who need to change.”

The Pro Environment Balloon Alliance also has emerged in the last decade to advocate for safe balloon practices on behalf of the industry. Both organizations advocate against releasing balloons and for popping and disposing of them after use.

“When it comes down to it, we all need to be working our buns off to protect the environment and make good choices,” said Kelly Cheatle, one of the organizers of the alliance.

For now, the balloon release will remain one of the Indy 500's many traditions.

Emily Hopkins covers the environment for IndyStar. Contact them at 317-444-6409 or emily.hopkins@indystar.com. Follow them on Twitter: @indyemapolis.

IndyStar's environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.