BALDWIN PARK -- It was a messy Thursday morning commute on the San Bernardino (10) Freeway in Baldwin Park after a big rig overturned and crashed through the central divider, triggering several other collisions.

The Toys "R" Us big rig was traveling eastbound just east of the 605 Freeway around 2:40 a.m. when it flipped over and slammed into the center divider, according to California Highway Patrol Officer Patrick Kimball.

The crash sent large amounts of concrete and debris into the westbound lanes, causing one vehicle to overturn and two big rigs to collide, according to the CHP.

The flying debris triggered accidents involving six other vehicles on the westbound side that were "hit by the big rig, struck debris, or struck by another vehicle trying to avoid the debris," CHP Officer Francisco Villalobos said.

Two people were taken to hospitals with moderate injuries while others suffered minor injuries.

It was unclear what caused the first big rig to crash.

All eastbound lanes of the 10 Freeway were shut down for several hours, as well as connector roads from the 605, causing traffic to back up for several miles.

The CHP says all lanes have since reopened.