Legionnaires’ Disease: Microscopic, Deadly—and Insurable


What the New York City Health Commissioner describes as “the largest outbreak of Legionnaires’ disease that we are aware of in New York City” has so far infected 97 people, but it is just one of many such outbreaks the United States can expect this year. The US Centers for Disease Control estimates 8,000-18,000 hospitalizations for Legionnaires’ disease annually—many of which result in death and/or severe life-threatening medical conditions.

The primary concern in outbreaks such as this is always for those infected by the disease, their loved ones, and those suddenly faced with the fear of contracting it. Understanding, preventing, and treating it are the highest priorities.

The Disease

Legionella bacteria are common and can be found in rivers, lakes and reservoirs. Bacteria growth occurs at temperatures around 68º – 113º F (20º – 45ºC), with the optimum temperature for bacteria virulence being human body temperature.

People can be exposed to Legionella when they breathe in a mist or vapor that has been contaminated with the bacteria. Unfortunately, it can have symptoms similar to many forms of pneumonia, making it difficult to initially diagnose.

Building and Property Risks

While legionella bacteria are found naturally in the environment, they can originate from ideal warm-water breeding grounds such as:

  • Water cooling towers (as suspected in the New York outbreak)
  • Hot tubs
  • Water systems incorporating an evaporative condenser
  • Hot and cold water systems (including water storage tanks)
  • Extensive plumbing systems
  • Any variety of plant or water system that contains water likely to exceed temperatures of 68º F (20ºC) and which may release a spray or aerosol of water droplets (either during day-to-day operation or when being maintained)

and then aerosolized via shower heads, faucet aerators, spas, air conditioner/cooling tower units, fountains and other exposure pathways.

With building water systems often implicated in its transmission, Legionnaires is of particular concern for building or property owners, who must worry about the potential liability and legal costs associated with this disease.

Mitigating the Risk of Legionnaires

It’s not something many of us want to think about on a regular basis, but risk managers and other stakeholders must contemplate this exposure and manage the risk accordingly. From both a human and a business standpoint, preventing an outbreak is of course the desired outcome.  Prudent risk management can include:

  • Risk assessment of water systems
  • The development of water management and monitoring plans
  • Safety processes and prevention protocols

Legionnaires’ Disease Can Be Covered

While most insurance policies exclude coverage for Legionnaires’ Disease via various “pollution” and “contamination” exclusions, many environmental insurance carriers have built in affirmative coverage grants to their forms via a modification to their definition of “pollutants” to include

legionella pneumophila in any structure on land and the atmosphere contained within that structure

Many companies are incorporating environmental liability insurance into their risk management strategy as an effective risk transfer solution to protect against the potential costs, liabilities, defense and reputational damages associated with this exposure.

About Anthony Wagar

Anthony is a Executive Vice President and the National Sales Leader for Willis Towers Watson's Environmental practi…
Categories: Environmental Liability, Real Estate | Tags: ,

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