Police shut down the westbound lanes on Chain of Rocks Bridge after approximately six cars crashed early Wednesday morning.
Eastbound Interstate 270 drivers were also affected; police had the roadway restricted to one lane, according to a KMOV report.
Drivers can avoid the area by taking Illinois 3 or I-255.
No additional information has been released by police.
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IDOT reported a significant backup on I-270, stretching from the bridge to Illinois 111.