OSHA was warned about this possibility in 2004! ... [a salient feature of that complaint is provided below]
Stagnant water (such as that which accumulates secondary to the ceiling-leak-’phenomena’), combined with ductwork problems and an endless source of exposure to microorganisms may constitute a legionella or pneumonia (causative agent) hospitable environment and it may be appropriate to consider the installation of ultraviolet germicidal lights in the ductwork systems, similar to those apparently studied in The Lancet, (2003, 362 (9898), 1785), if such systems are not already in use and are not in variance with intermittent contact with volatile chemicals that may coincidentally ’seep’ into the ductwork.
That complaint resulted in a citation of MSKCC for 'serious' violations:
To date, MSKCC's Facilities Team continues to have a work product that results in the compromising of employee and patient safety.
In the past MSKCC had to abandon a building when they could no longer deny that their employees were being subjected to poison(s) [carbon oxide(s)]; In the past MSKCC built a laboratory building strewn with poisons/toxins and knowingly did not install ductwork controls; MSKCC misstated the facts relative to the severity of a 'chlorine' spill that required an FDNY ordered building evacuation.