The Arizona Department of Transportation reported Tuesday that a collision last week along Interstate 10 in Pinal County led to the discovery of 286 pounds of suspected fentanyl pills.

Four out of every 10 pills laced with fentanyl contain at least 2 milligrams of the synthetic opioid, a potentially lethal dose, according to the U.S. Drug Enforcement Administration.

Based on those figures, there was enough fentanyl in the seizure to potentially kill more than 500,000 people, DPS officials said in a release.

Troopers responded to reports of a single-vehicle collision at about 7:30 p.m. Feb. 16, on eastbound I-10 at Casa Blanca Road in Sacaton.

A pickup truck had rolled over, ejecting the driver, who was taken to a hospital with life-threatening injuries, according to DPS

During their investigation, troopers discovered packages of pills concealed throughout the truck. In total, troopers seized approximately 286 pounds of suspected fentanyl pills - or approximately 1,297,000 pills - from the vehicle.  

The estimated street value of the fentanyl seized is approximately $5.1 million, according to DPS.