Construction of the antenna atop One World Trade Center as seen from Chopper 880 - Feb. 15, 2013 (credit: Tom Kaminski / WCBS 880)

NEW YORK (CBSNewYork/AP) — Three World Trade Center construction workers have been charged with possessing and selling marijuana at the site in Lower Manhattan.

The arrests Friday are part of a seven-month investigation by the site’s integrity monitor and the Port Authority inspector general.

The investigation began after “one of our integrity monitors on the hub project one day got a strong odor of marijuana,” said Port Authority Deputy Inspector General Mike Nestor.