VAN BUREN COUNTY, Mich. -- The Van Buren County Sheriff's Office reports deputies, medical first responders, and the Paw Paw Fire Department responded to the 24000 block of M-43 on the report of a two-vehicle roll-over crash on Tuesday around 3:12 p.m.

Prior to the first responders' arrival, multiple civilians, including two military personnel and two doctors, had stopped to help the injured, and were able to provide emergency medical triage to the severely injured vehicle occupants.

Deputies say a Ford Econoline Van, driven by a 32-year-old Van Buren County man, was traveling west on M-43 with six passengers.

The van then crossed the center line and crashed into a GMC Yukon XL, driven by a 37-year-old Jackson, Mich. man.

The report states the Yukon's driver was able to swerve just enough to avoid a direct head-on collision.

Following the initial crash, the report states the van rolled over, ejecting one woman.

Multiple occupants were then entrapped within the wreckage of the van.

Statements from the van's driver and front seat passenger, given prior to being taken to the hospital for medical care, lead deputies to believe the 32-year-old may have "nodded off" due to extreme fatigue. 

Neither alcohol nor drugs are believed to be a factor at this time.

Both drivers and all six passengers of the van were taken to the hospital for injuries sustained in the crash. 

Four occupants are said to be in critical condition.

There's no other information regarding medical status known at this time.

M-43 was shut down for around three hours.

Authorities say the incident remains under investigation and will be forwarded to the Van Buren County Sheriff's Office for review, once completed.