(KMOV) -- Emergency crews were called to the scene of two school bus accidents on Friday morning.
The first bus crash happened just before 7:00 a.m. on on I-70 near 10 th Street. Eastbound I-70 was closed between Salisbury and Madison while crews worked to clear the accident. Traffic in that area was backed up for miles at the peak of the morning rush.
According to Bruce Ellerman with Voluntary Interdistrict Choice Corp, a vehicle cut-off the bus on I-70. The bus driver swerved to avoid the vehicle and side-swiped a second vehicle. The bus was then rear-ended by a third vehicle, sending the bus over the median that separates eastbound I-70 from the express lanes.
There were about 20 students on board at the time of the crash. The students were headed to Mehlville High School.
According to Ellerman, one of the students is pregnant and was taken to St. Mary's. Her condition is unknown at this time.
Seven students were taken to Cardinal Glennon Hospital. None of the injuries are considered serious.
According to a hospital spokesperson, all seven of the students have been released.
The second school bus accident happened around 7:40 a.m. on Natural Bridge and Newstead.
The accident involved at least one other vehicle that was heavily damaged.
According to St. Louis police, the driver of the vehicle involved in the crash suffered a heart attack and is hospitalized.
It is unclear if the driver suffered the heart attack before or after the accident.
No word yet if there were any students on board at the time of this crash.
KMOV's Edward Burch contributed to this story