Nantucket, Massachusetts – Long known as a summer retreat for the rich and famous, Nantucket Island is now making headlines for a very different reason: its sewage is laced with cocaine at levels 50% higher than the U.S. average, according to recent testing.

Data released by the town’s health department revealed that wastewater samples collected from June 18 to July 28 contained an average of more than 1,500 nanograms per liter of cocaine, compared with the national benchmark of 1,000 nanograms. The findings come from samples analyzed by Biobot Analytics, a Cambridge-based startup born out of MIT that specializes in wastewater epidemiology.

The six-week study also detected traces of fentanyl, methamphetamine, and the tranquilizer Xylazine, alongside prescription opioids such as codeine, morphine, and oxycodone. While fentanyl and meth levels were actually below both the national and Northeastern averages, the cocaine spike stood out to experts.

“I think it’s interesting that cocaine was so high. And I was surprised fentanyl was so low, because fentanyl is in everything,” said Dr. Timothy Lepore, founder of Addiction Solutions of Nantucket, in an interview with the Boston Globe. “I thought fentanyl would be higher. I’m interested to see in the depths of winter, when people with large amounts of disposable income have left the island.”

Nantucket, home to roughly 14,000 year-round residents, is transformed each summer into a bustling playground for celebrities, Wall Street financiers, and political elites. Among its well-heeled property owners are Barstool Sports founder Dave Portnoy, actor Ben Stiller, and former Google CEO Eric Schmidt. With multimillion-dollar waterfront homes, yacht clubs, and an exclusive social calendar, the island has long carried a reputation for high-end revelry.

But the wastewater results suggest that beneath the polished image lies a drug culture intertwined with that seasonal affluence. The testing was conducted at the Surfside Wastewater Treatment Facility, which covers about 70% of the island’s population. By analyzing human waste, researchers are able to estimate levels of drug consumption across entire communities—a growing tool for public health surveillance.

Nantucket’s public health director, Roque Miramontes, urged caution in interpreting the results. “As this activity is still in its early stages, additional baseline data is needed to provide a clearer picture,” he said. “For high-risk substances and opioids, a sustained increase over several weeks may be a stronger indicator for public health intervention.”

That note of restraint reflects the scientific reality: wastewater data is still a relatively new field. Variations in testing sites, collection times, and population size can all influence readings. Still, the results paint a snapshot that aligns with the island’s social dynamics—an influx of affluent vacationers bringing with them habits that may not mirror the year-round community.

The stark contrast between high cocaine readings and lower-than-expected fentanyl figures is particularly notable given national trends. Across the U.S., fentanyl continues to fuel record overdoses, often laced into cocaine, heroin, and counterfeit pills. That Nantucket shows the reverse—booming cocaine but lower fentanyl—suggests a different drug landscape, at least for now.

Experts say the winter testing will be key. Once the summer crowds vanish, leaving a quieter island behind, researchers will be able to assess whether the elevated cocaine levels were tied to the seasonal influx of wealthier visitors or if they reflect a broader, ongoing issue.

In the meantime, the data has sparked conversation among residents and public health advocates. For some, the results confirm suspicions about the party-heavy summer scene. For others, they highlight the importance of investing in treatment and prevention services—even in places that outwardly project affluence and stability.

Dr. Lepore, who has spent decades working in addiction medicine on Nantucket, stressed that drug use knows no boundaries. “The island may look pristine, but it is not immune,” he said. “We need to use data like this to confront the reality.”

For now, the yachts remain moored, the beach parties continue, and the headlines about Nantucket’s hidden undercurrent ripple far beyond the island. What the next round of testing reveals—when the spotlight fades and the celebrities head home—may determine whether this was a seasonal spike or a persistent trend.