CHARLOTTE, N.C. -- NBC Charlotte uncovered new and concerning details about Monday's school bus accident in Union County, which left four kids hurt, including one who was seriously burned.
The bus leaked hot antifreeze where the kids were sitting.
Our investigation found this same issue happened at least two other times before, and the state sent out a warning to all districts in North Carolina.
These students were headed home from Porter Ridge Middle on Monday afternoon.
In February, four Durham students were burned when a pipe burst spraying anti-freeze on students.
And back in 2013, the same thing, in Wake County. That incident prompted a state-issued memo to all school districts recommending that all Thomas MVP rear engine buses be inspected immediately and parts replaced as needed.
A spokeswoman for Union County tells NBC Charlotte they've inspected the buses as required by the memo. We checked and found the bus in Monday's incident was given the all clear on April 15.
But we've also learned there are 300 buses that could have this same issue in school fleets statewide.
The bus company issued this statement:
"Thomas Built Buses offers its sincere condolences to all individuals involved. The safety of the children our buses transport is of the highest importance to our company and our employees. Until this incident is investigated and we have a clear picture of what happened we will have no further comment on this matter."