The crash occurred along Highway 20 near mile marker 44, according to the California Highway Patrol.
The CHP reported the crash shortly before noon.
A vehicle rolled over and trapped at least one subject who had injuries, according to the report.
The highway's eastbound lane was blocked with emergency vehicles, with firefighters from Northshore Fire and Lake County Sheriff's deputies on scene.
An air ambulance was requested because a 2-year-old child was reported to have head injuries and needed to be transported to Children's Hospital Oakland.
Further details about the crash, how many vehicles issued and the names of those involved were not immediately available.
The area where the Friday incident occurred has seen a number of serious crashes in recent years, as Lake County News has reported.
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