The crash was reported at 5:47 a.m. at Puente Avenue, according to the California Highway Patrol's traffic log.
AIR7 was over the scene where a smaller box truck appeared to have collided into the back of a semi. First responders were seen working to rescue a person trapped in the crushed cab of the box truck.
That man was eventually pulled out by first responders, and appeared to be alert. He was taken to the hospital in unknown condition.
Additional details about the crash were not available.
All eastbound lanes closed as a result. At least three lanes were reopened by 7 a.m.
DEVELOPING: We will add more details to this report as they become available.