Giving Legal Teeth to the Fight Against Legionnaires' Disease

City officials say a handful of cooling towers in the South Bronx are the source of a Legionnaires' Disease outbreak that has affected 100 people, killing ten of them, as of Thursday afternoon.

As New York City buildings have gotten bigger, more and more are using such cooling systems, where bacteria are prone to grow. The city wants to impose new regulations that would take industry standards and, for the first time in the United States, give them the force of law.

Cooling a large building generates heat, and to “reject” that heat, as engineers put it, HVAC systems use cooling towers filled with water. And where there's water there's potentially algae, mold and bacteria, including legionella pneumophila.

"You have microorganisms, but with good effective treatment programs, they're kept in manageable numbers," said Bill Pearson.

Pearson works for Southeastern Laboratories, a water treatment manufacturer in Raleigh, North Carolina, and he helped draft new cooling tower guidelines for the American Society of Heating, Refrigerating and Air-Conditioning Engineers, or ASHRAE.

Building owners who install HVAC systems with cooling towers hire licensed professionals to perform regular maintenance — somewhat like a swimming pool owner retaining a cleaning service. They check the chemicals, filters and overall bacteria levels, and they do a thorough cleaning once or twice a year.

"There are treatment plans in place where you have a monthly injection and monthly readouts," said Lorey Flick Roberts, of ADS Engineers. "A technician will come out to take some water samples to say, 'Great, you have no growth, things are looking good, you get the A-okay.'"

But from time to time, cleaning regimens break down, bacteria flourish and outbreaks ensue. In January, an outbreak at Coop City in the Bronx sent eight people to the hospital.

Legionella is not considered a virulent pathogen, but it can cause pneumonia in an estimated five percent of the population who are elderly or have underlying health conditions. Legionnaires' Disease kills between five and 30 percent of those who contract it.

The city already requires permits to install cooling towers. A forthcoming bill from the de Blasio administration and City Council would further require building owners to register the towers with the city and would put HVAC industry standards into law for the first time in the United States.

Oners would be subject to fines, unless they provided proof of maintenance and inspection.