Authorities seized 400 grams of fentanyl during two investigations in Nassau County this week.
The seizure is the biggest in the county’s history.
Police confiscated $130,000 worth of the opioid from a Hempstead home, enough to cause 150,000 fatal overdoses.
Five hundred grams of cocaine and eight firearms were also discovered during the probe.
Authorities say the leader of the drug ring, Ricky Jackson, allegedly ran his operation from a federal prison medical center in Massachusetts.