ANTIOCH (CBS SF) — A bumper in the road triggered a major-injury pileup on Highway 4 that shut down all westbound lanes near A Street, in Antioch.

The highway was reopened at 7:48 p.m., according to the California Highway Patrol.

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The crash was caused by a bumper blocking a lane of traffic. When a Toyota sedan, with passengers inside, stopped in the lanes of traffic behind the bumper, a minivan collided with the sedan. There were 3 passengers inside the minivan.

The crash was reported at 6:20 p.m. according to Contra Costa County Fire Department.

When firefighters arrived they found at least 4 disabled vehicles across all lanes and several people on the ground. At least 10 were being treated.

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Authorities said at least 3 of them were in critical condition.

Five ambulances arrived on the scene and 4 helicopters landed on the freeway to transport victims.

Authorities said ten victims were transported to nearby hospitals. One child was airlifted to Benioff Children’s Hospital in Oakland. Two adults were transported to UC Davis.

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The crash caused a major backup on Highway 4.