MORENO VALLEY (CBSLA) — A 5-year-old boy who was critically injured in a deadly charter bus crash in northern San Diego County was airlifted Sunday to a Moreno Valley hospital, authorities said.

The child was among the 21 passengers in a charter bus traveling from El Monte to Tijuana that crashed Saturday morning on rain-slicked southbound Interstate 15, south of state Route 76, near Fallbrook.

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Three women were killed in the crash and 18 others were taken to hospitals — five to Palomar Medical Center in Escondido, five to Inland Valley Medical Center in Wildomar and eight to Temecula Valley Hospital, according to California Highway Patrol officials. Three of the hospitalized patients sustained major injuries.

“Thankfully, heavy rescue systems — ropes and those types of things — were not required in order to extricate the victims,” Chief Stephen Abbot, of the San Diego County Fire Department, said. “And, thankfully, all victims were removed from the scene within 30 minutes of arrival.”

The child, who was originally taken to Inland Valley Medical Center, was airlifted Sunday to Riverside University Health System Medical Center in Moreno Valley to be treated for a head wound.

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According to CHP, the accident happened at about 10:30 a.m. when the charter bus — owned by El Monte-based Executive Lines Inc. — slid off the I-15 during a heavy rainstorm, down an embankment and landed on its roof. Most of the injured passengers were either ejected or escaped from the bus. Officials said the bus was equipped with seat belts, though few passengers were wearing them at the time of the crash.

According to the U.S. Department of Transportation, the bus company’s records show that it has passed all inspections over the past two years and that there have been no reports of crashes.

The bus driver, from Whittier, was questioned by officials and voluntarily gave a blood sample. Investigators said the driver, whose name has not been released, was cooperating fully with the ongoing investigation.

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(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)