An 18-wheeler overturned around 8 a.m. spilling an oily liquid called styrene monomerm, according to the Department of Public Safety.

The liquid -- used to make plastics and polyster -- can cause everything from
dizziness to liver damage or even death.

Because it is highly flammable and dangerous, I-45 is closed in all directions. Traffic is being rerouted to the feeder roads.

DPS officials say they hope to have I-45 open again by 5 p.m.

The trucker wasn't removed from the wreckage until about three hours after the accident. He was air lifted to a Houston hospital.

As a precaution, a nearby RV park was also evacuated.