The first crash- reportedly in the "new bridge" construction zone south of Missouri (M) 58 was reported to South Metro Fire dispatchers at 2:49 p.m..
When the first emergency unit arrived about 5 minutes later- it was confirmed there were "multiple vehicles including a semi with non-hazardous materials involved" with "all occupants" of the vehicles involved "out" of those vehicles.
Within 2 minutes of that report- a "second" crash is reported just north of the original one.
This 2nd wreck is worse- also involving "multiple-vehicles- semi-trucks with (hazardous materials) and extrications" of occupants.
All available northern Cass county EMS units have been sent- and 3 medical helicopters are enroute.
Two seriously-injured people were transported to a south KC-MO trauma center- a female and a "29-year-old male" whose small car was struck from behind while waiting in stopped traffic by a semi-truck.
Only 1 medical helicopter was needed- they transported the 29-year-old male.
There were no other patient transports heard- although a 3rd serious to critical injury was reported- and there were "numerous patient refusals" of people involved in both wrecks.
Cass County Sheriff's department and the MO Highway Patrol are investigating the scene..