When you don’t believe in germ theory, the world is your oyster—or maybe your bathtub.

Over the weekend, America’s top health official, Robert F. Kennedy Jr., shared pictures on social media of himself fully submerged in the sewage-tinged waters of Rock Creek in Washington, DC. His grandchildren were also pictured playing in the water.

The creek is known for having a sewage overflow problem and posing a health hazard to any who enter it. The National Park Service, which manages the Rock Creek Park, strictly bars all swimming and wading in Rock Creek and the park’s other waterways due to the contamination, specifically “high levels of bacteria.”

A notice on the NPS website advises “Stay Dry, Stay Safe,” warning, “Rock Creek has high levels of bacteria and other infectious pathogens that make swimming, wading, and other contact with the water a hazard to human (and pet) health. Please protect yourself and your pooches by staying on trails and out of the creek. All District waterways are subject to a swim ban—this means wading, too!”

In images shared on social media, Kennedy can be seen getting fully underwater, including his head, and then splashing around with several of his grandchildren. Kennedy, who does not have any background in medicine or science, was a long-time anti-vaccine advocate before President Trump appointed him to be health secretary. In a 2021 book, Kennedy indicated that he does not believe in germ theory, the fundamental concept that microscopic pathogens, such as those abundant in sewage, are the cause of disease.