A devastating multi-vehicle crash on the 10 Freeway in Ontario, California, left three people dead and two others hospitalized on Tuesday afternoon, after a semi-truck slammed into stopped traffic at high speed.

Authorities say the 21-year-old big rig driver was arrested on suspicion of driving under the influence of drugs after losing control and colliding with multiple vehicles. The impact triggered a massive chain-reaction crash involving at least eight vehicles, including four tractor-trailers.

Witnesses described the scene as chaotic and horrifying, with cars crushed between trucks and flames engulfing parts of the freeway. “It was unreal,” one driver said, recalling how responders rushed to pull victims from the wreckage.

The collision forced lane closures for several hours, bringing traffic on one of Southern California’s busiest freeways to a standstill as firefighters and emergency crews battled the blaze and cleared debris.

Investigators with the California Highway Patrol (CHP) are now examining whether excessive speed and impairment were factors in the deadly pileup.

The tragic incident has reignited concerns over commercial driver safety and the dangers of drug-impaired driving on U.S. highways.