Horrible Smell on Pershing in DeBaliviere Place

A catch-all forum for urban discussion. If it doesn't fit elsewhere, post here.
What IS that smell??? Smells like a sewer all along Pershing between Union and DeBaliviere. It was there before they started construction on the new apt complex, and it's stronger near Union (or seems to be so). Seems to be really bad in the last few weeks.

Who do we call to investigate?
MSD and St Louis Citizen's Service Bureau