A map from 1968 shows the six-acre cemetery which could be disrupted by the rebuilding of Oak Park Avenue. View Full Caption Northwest Chicago Historical Society/Matt Schademann; DNAinfo/Heather Cherone

DUNNING — An exploratory dig starts Monday to determine whether efforts to rebuild Oak Park Avenue will unearth thousands of bodies buried in a long-forgotten Dunning cemetery that holds the remains of Chicago's poorest and sickest residents who died between 1890 and 1912.

Oak Park Avenue was closed to traffic between Irving Park Road and Forest Preserve Drive Friday as city engineers and archaeologists excavated the area to determine whether there are graves in the path of the roadway reconstruction project, said Mike Claffey, a spokesman for the Chicago Department of Transportation.

No graves will be relocated as part of this phase of the project, Claffey said.

If graves are found, city officials will consult with state and local agencies, including the Illinois Historic Preservation Agency, before taking steps that would disrupt remains, Claffey said.

The work will be conducted "with the utmost care and respect for the deceased," Claffey said.

Traffic in both directions will be detoured via Harlem Avenue, officials said.

DNAinfo Chicago first reported that as many as 10,000 bodies could be buried under what is now Oak Park Avenue in a 6-acre cemetery on the grounds, based on the work of Barry Fleig, the former cemetery chairman of the Chicago Genealogical Society.

Hear reporter Heather Cherone explain the history of the site and how it may impact the construction project:

More than 2,000 babies were buried in the cemetery, Fleig said, citing county records and coroner's reports.

"This is an entire cemetery that has been forgotten about," said Fleig, who is assembling a database of about 38,000 Chicagoans buried in what is now the heart of Dunning, but was once the grounds of a Cook County poorhouse and later an asylum for the mentally ill.

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