As part of “The BEACH,” an interactive installation from the art and architecture collective Snarkitecture, the National Building Museum’s Great Hall is currently filled with nearly a million plastic balls. D.C. residents and tourists alike can laze the afternoon away in this sea of hollow capsules that brings back memories of childhood afternoons spent in IKEA’s ball pits. But think twice before you dive into the synthetic ocean: Buried in the depths, among lost phones and shoes, could be some pretty icky bacteria.

Piper Grosswendt visited the Building Museum on Tuesday afternoon with a friend. They spent about 45 minutes chatting and hanging out—while the installation was fairly crowded with young kids, teenagers, and twentysomethings like them, they didn’t physically run into anyone.

On Wednesday, Grosswendt noticed that her eye looked red and when it continued to worsen, she went to a walk-in clinic to have it checked out. The diagnosis: bacterial pink eye. Based on her timeline and the way pink eye is contracted, Grosswendt suspects she caught it at “The BEACH.” The nurse at the clinic agreed.

Another guest, who visited “The BEACH” when it opened in early July, came down with a nasty cold just two days after her visit, causing her to miss two days of work. She believes she may have caught it from someone who was in the pit at the same time as her, if not from the balls themselves.

In order to avoid these types of incidents (and to brush off accusations that ball pits are just homes for festering germs), the balls, manufactured by North Carolina-based 21st Century Products, Inc., feature an anti-microbial component that’s incorporated in the plastic before it’s molded. In addition, the exhibit is cleaned daily and the balls are regularly sprayed with another antimicrobial agent.

Brett Rodgers, the Building Museum’s director of marketing and communication, says staff has not heard of any illnesses beyond Grosswendt’s, who emailed the museum once she got diagnosed. They plan to install more hand sanitizer stations in the exhibit and encourage visitors with very contagious illnesses to avoid the museum until they recover.

Despite her ailment, Grosswendt still enjoyed her time at “The BEACH.” “It’s a bummer, because it’s really fun and a minor public health risk,” she says. “I just don’t want other people to get pink eye.”

Have you heard any other stories of “BEACH”-related ailments? Let us know in the comments.