Officers with the Colorado State Patrol seized 114 pounds of pure fentanyl on a highway on June 20.
An official with the Colorado State Patrol told Fox News that the agency stopped a car that was headed toward Denver on Interstate 70 near Georgetown when they made the discovery.
The 114 pounds of pure fentanyl powder was found below the passenger and driver seats, reachable by a trap door, and were in 48 one-kilo bricks.
The Colorado Gazette first reported on the discovery.
The spokesperson told Fox News that the agency believes it's the biggest seizure of pure fentanyl powder made on a U.S. highway.
Colorado State Patrol Smuggling, Trafficking and Interdiction Unit Captain Bill Barkley said that the agency isn't disclosing the identity of the driver due to potential retaliation from Mexican cartels, and didn't state why the car was stopped.
"They don’t care about anything but making money," Barkley said.
Barkley said that its investigation into the drugs is being done in conjunction with the Drug Enforcement Administration.
He said that the drugs are continuing to pour into the United States and Colorado, stating that the cartels "engineer" the trap compartments.
"It’s a continued cat and mouse game between law enforcement and cartels. They actually hire people to engineer trap compartments," Barkley said. "Whether or not it’s on I-70 or on I-25, or it’s on secondary highways coming into our state, I would bet every hour of every day there is something."
Figures by the DEA say that one kilogram of fentanyl can kill up to 500,000 people. The bust on June 20 had the potential to kill over 25 million people, according to those figures.
From January to May, over 2 million dosages of fentanyl units were seized by Colorado authorities, which surpasses the amount form last year.
Fox News' Louis Casiano contributed to this report.