GREAT NECK, N.Y. (CBSNewYork/AP) — The sale of $19,000 in drugs to undercover Long Island police officers has led authorities to a massive operation that they say had been supplying the entire East Coast with drug paraphernalia and packaging.

Nassau County police and U.S. Drug Enforcement Administration agents on Wednesday arrested three men in Great Neck who allegedly attempted to sell ketamine and fentanyl to undercover officers.

Authorities raided the men’s storage facility in Queens and found 2.5 million glassine envelopes commonly used to package drugs like cocaine and heroin, Newsday reported.

“The amount of fentalyl that is there could take out a whole neighborhood,” Deputy Commissioner Patrick Ryder said, adding that one of the suspects worked at a dentist’s office and that is how he obtained the fentanyl.

Nassau County District Attorney Madeline Singas said the drug is so powerful it’s used to tranquilize elephants.

Nearly 500 people died from opioid overdoses on Long Island in 2016.

Police say they’re still seeking $600,000 in bank accounts linked to the suspects, who include a 50-year-old man and his 28-year-old son.

Investigators believe the trio is responsible for six overdoses.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)