Wastewater results show unexpectedly high cocaine levels on Nantucket, reaching up to roughly three times the national average, with notable peaks in mid-October and again near the Christmas period.

Early September data already indicated cocaine levels about 50% higher than the national average, followed by surges in October and December that were characterized as dangerous amounts.

Measured peaks hit about 2,949 ng/L on 14 October and exceeded 2,800 ng/L near Christmas, substantially above the US average of roughly 900–1,000 ng/L, while fentanyl and methamphetamine stayed below regional and national averages.

Nantucket’s public health director noted that the island’s seasonal population surge, when numbers quadruple in summer, creates unique behavioral health challenges.

Nantucket began wastewater testing last summer to monitor high-risk substances and opioids in the community.

Officials described the wastewater data as a tool to identify patterns and guide timely, evidence-based interventions, including educational outreach, screening, or peer-led recovery support if spikes persist.

Testing detected cocaine metabolites (benzoylecgonine) and signs of unconsumed cocaine dumping into the sewer, indicating both personal use and disposal contribute to wastewater cocaine levels.

The report identifies cocaine as the island’s primary recreational drug of concern, with fentanyl and methamphetamine remaining comparatively low.