At least 19 people were injured when more than 75 vehicles were involved in a massive pileup on Interstate 70 in Colorado, according to state and local officials.

The crash was first reported near the Eisenhower Tunnel, a critical mountain passage through the Rockies west of Denver. The collision occurred on the eastbound lanes near milepost 216, according to the Colorado State Patrol.

The Clear Creek County Sheriff's Office said an estimated 75 or more vehicles were involved in the chain-reaction crash. Authorities reported that 19 individuals were transported from the scene with injuries ranging in severity.

Officials have not yet determined what caused the pileup. The incident forced a full closure of all eastbound lanes for several hours, while westbound traffic was partially restricted to allow for emergency response operations and medical staging.

Images released by authorities showed snow-covered roadways at the time of the crash, with later photos revealing icy conditions and snow accumulation along the shoulders, suggesting hazardous winter driving conditions likely played a role.

The Colorado State Patrol is leading the ongoing investigation as crews work to reconstruct the sequence of events and assess contributing factors such as weather, visibility, and road surface conditions.