OKLAHOMA CITY (KFOR) – An investigation has led to what is believed to be the largest contraband seizure in the history of an Oklahoma agency.

Officials say the investigation by the Oklahoma Department of Corrections’ Office of the Inspector General led them to the bust, which helps in the agency’s ongoing efforts to keep contraband out of prisons.

Information gathered by the Criminal Interdiction Division of the OIG led investigators to a storage unit in Oklahoma City.

After getting a search warrant, agents discovered a warehouse-sized operation for contraband drops, which contained everything from drugs and tobacco to cell phones and drones.

Officials say they seized 30 pounds of marijuana, 2.2 pounds of methamphetamine, 2,400 cannabis pills, a large number of cannabis edibles, 35 pounds of tobacco, 31 cell phones, and two drones.

Agents also found a supply of cell phone chargers, lighters, grappling hooks, and plexiglass.

Authorities allege that all of the items were intended to be smuggled into Oklahoma prisons.

Officials also found four firearms, a stockpile of ammunition, and $8,500 in counterfeit United States currency. The counterfeit $100 bills have been turned over to the U.S. Secret Service.

“This incredibly large seizure is the direct result of a commitment to preventing these things from winding up in one of our facilities where they pose a danger to inmates and staff alike,” Inspector General Ted Woodhead said. “They had everything there that you would need to try to get a contraband drop into a facility—some of the drops were already wrapped up and ready for delivery.”

Woodhead estimates that the contraband was worth “hundreds of thousands of dollars.”

“Busting up this warehouse operation for contraband drops on the heels of the major fentanyl seizure early this month shows the growing scale of the contraband problem,” said ODOC Director Scott Crow. “It’s a plague faced by corrections agencies in every state, and we will continue to deploy the resources necessary to shut down the contraband rings in Oklahoma.”