ST. LOUIS • An old Coca-Cola plant redone as lofts held promise as a profitable way to buoy a south St. Louis neighborhood. Instead, the struggling site has embroiled the developers in a dispute over why the project defaulted on a federally insured loan.

Prominent in the controversy are a critical audit by the Department of Housing and Urban Development, a longtime St. Louis developer, a buried oil tank and a disgraced former HUD official.

In 2010, work got under way on the Temtor, the name developers gave the Coke syrup plant that they renovated as apartments and commercial space. The project has succeeded as a residential address but it also has struggled to attract and keep commercial users.