(KMOV) -- A gas main break that shut down parts of Dunn Road in north St. Louis County on Wednesday morning is under investigation.
The gas main has been leaking on the construction site of the National Archives and Records Administration building since Tuesday morning.
The break is right by Hazelwood Middle School.
Some drivers reported smelling natural gas from Interstate 270.
Laclede Gas is now trying to figure out what caused the leak.
Westbound Dunn Road remains closed between Bellfontaine Road to Kirby School.
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