How Can You Tell?

By Semperpapa

The NY Daily News reports that the United Nation Security Council had to be evacuated on Tuesday for about 90 minutes.
The evacuation was prompted by a foul smell of sewer gases that pervaded the assembly building.

The FDNY tested the building for hazardous fumes and later cleared it by stating that the smell most likely came from sewer spillage of some sort.

With all the scum that is usually roaming the United Nations, how was the smell even noticed?
How can you tell that there is something other than normal smell of crap inherent with the United Nations crowd?
Was Ahmedinejad cooking again?

Just curious.