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What New Yorkers Need to Know About Legionnaires Disease in NYC

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Last Updated on September 9, 2019


The outbreak of Legionnaires’ Disease in NYC has raised many questions

While it’s a relief to know that the recent outbreak of Legionnaires’ Disease in NYC is over, many New Yorkers still have lingering questions and concerns about Legionnaire’s Disease in NYC as well as the new legislation recently passed in the city to prevent further outbreaks. Even though the outbreak is officially over, those of us who live and work in NYC will be dealing with the ramifications for quite some time.

Everyone is talking about this issue, and you may be unsure about whether you can trust what you’re reading and hearing about Legionnaires’ Disease in NYC. So we have put together a list of what those of us who live and work in NYC need to know, and where to get reliable and accurate information.

How common is the legionella bacteria and Legionnaires’ Disease?

Legionnaires’ Disease is caused by inhaling droplets of water that contain a bacteria called Legionella. Legionella bacteria “are widely present at low levels in the environment: in lakes, streams, and ponds,” according to the Occupational Safety & Health Administration (OSHA). At these low levels, the bacteria present very little risk. However, the risk of infection is much greater when the bacteria grow in high concentrations in warm, stagnant water systems such as HVAC cooling towers, hot water heaters, and hot tubs.

In the United States, there are between 10,000 and 50,000 cases of Legionnaires’ Disease each year. Many are sporadic cases and not related to a larger outbreak. It’s important to note that the disease is not spread from person-to-person contact, and among people who are exposed to the bacteria, only about 5% will get sick. Among those who do become ill, the most serious cases and fatalities are seen in people with preexisting medical conditions and weakened immune systems.

For more information about the disease, see the following resource from the US Centers for Disease Control and Prevention (CDC): Legionella (Legionnaires’ Disease and Pontiac Fever).

How and where does the Legionella bacteria grow and spread?

The Legionella bacteria can multiply in warm, stagnant water systems with temperatures between 20°C-50°C (68°-122°F). Rust (iron), scale, and other microorganisms can also promote the growth of Legionella.

According to OSHA, these water systems are of greatest concern with regard to the growth of Legionella bacteria and the possibility of causing infection:

  • cooling towers or evaporative condensers
  • evaporative coolers (swamp coolers)
  • humidifiers
  • misters
  • showers
  • faucets
  • whirlpool baths

For more information, read OSHA’s Legionnaires Disease: Facts and Frequently Asked Questions.

Is air conditioning safe from Legionnaires’ Disease in NYC?

The news about contaminated cooling towers in the South Bronx have caused people to wonder if water towers and drinking water are at risk, and even if walking into air conditioned spaces is unsafe. The New York City Department of Health and Mental Hygiene has assured us that the answer is no, and that the water supply and water features such as fountains and pools, are all safe and unaffected. There’s also no need to be concerned about Legionnaires’ Disease in NYC from window air conditioners and other air-cooled residential and commercial air conditioning systems.

For more information from the NYC Department of Health regarding the outbreak of Legionnaires’ Disease in NYC and risk factors, read Legionnaires’ Disease.

How can Legionnaires’ Disease in NYC be prevented?

According to OSHA, preventing Legionnaires’ Disease means taking steps to prevent the water conditions that allow the bacteria to grow to high levels, such as:

  • Regularly maintaining and cleaning cooling towers and evaporative condensers with twice-yearly cleaning and periodic use of chlorine or other effective biocide.
  • Keeping water heaters at  60°C (140°F), although this may not be advisable for homes with small children or elderly people at risk for being scalded by hot water.
  • Avoiding warm, stagnant water conditions such as large water tanks exposed to sunlight.
  • Frequently flushing unused water lines.

Read more recommendations from OSHA: Legionnaires Disease: Control and Prevention.

What is being done to prevent more cases of Legionnaires Disease in NYC?

A few weeks ago, the New York City Council passed new legislation that requires the registration, inspection and disinfection of all cooling towers as a preventative measure against Legionnaires’ Disease in NYC. The new law requires building owners to register all cooling towers with the city no later than September 17, and also register any new cooling towers before putting them into use.

In addition, the NYC Health Commissioner has issued an order requiring all cooling towers to be inspected by an environmental consultant and then disinfected. Records of inspections and disinfection must be kept and presented to city inspectors upon request.

To register a cooling tower online, go to: NYC Cooling Tower Registration Portal.

For further information:

Does your building have a cooling tower? If so, what must you do to comply with the new law?

Cooling towers are typically part of a certain type of heating and air conditioning system that uses recirculated water to control temperature. They can also be used for industrial processes. If you’re not an HVAC expert, you may not be certain whether your heating and cooling system includes a cooling tower. Your first call should be to your HVAC maintenance company, who can explain what type of equipment you have and what steps you must take to be safe and stay in compliance with the new regulations.

This NYC Department of Health publication can also help you identify a cooling tower if you have one, as well as answer other questions about complying with the new cooling tower regulations and preventing Legionnaires’ Disease in NYC:

Guidance for Business Owners: Cooling Towers and Health Commissioner Order

If you are concerned that your current HVAC service provider is not up to the task of helping you comply with the regulations, it may be time to think about making a switch. Read our helpful guide to learn more about easing the transition: Contract Confidence: Transitioning to a New HVAC Service Provider.

Get Your Free Guide to Vetting HVAC Service Providers

How can residents of buildings with cooling towers make sure buildings are in compliance?

If you live in a NYC high rise apartment building with a cooling tower, it’s in your best interest to be aware and concerned about your building’s compliance with the new cooling tower regulations designed to prevent Legionnaires’ Disease in NYC. The city has released guidelines for residents about how to ask your building management to register your cooling tower. For more information, go to: Registering Building Cooling Towers.