Legionnaires Disease Expert WitnessThe federal government estimates that cases of Legionnaires’ disease have almost quadrupled in the past fifteen years, and nearly every case could have been prevented. See Lena H. Sun, “Legionnaires’ outbreaks: Cases nearly quadrupled in 15 years,” The Washington Post, Jun. 7, 2016. Some 5,000 people were diagnosed in the past year, and the consequences have been grave, both in terms of health and the costs involved in treating the disease. See id. Moreover, according to some legal professionals, “With the increasing number of reported diagnoses and the serious, and often fatal, nature of Legionnaires’ disease, as well as the fact that a single outbreak can affect dozens, or even hundreds, of people, plaintiffs’ lawyers have turned their attention to this emerging risk.” Thomas P. Bernier & Susan E. Smith, “The Standard of Care Defense in Emerging Toxic Tort Claims,” For the Defense, Apr. 2014. The dramatic increase in the number of Legionnaires’ cases, coupled with the magnitude of the damages it can cause, have led to a rise in toxic tort litigation implicating myriad parties. This article examines the legal implications of the phenomenon and the role Legionnaires disease expert witnesses, among others, will play in litigation.


According to the Centers for Diseases Control (CDC), between 8,000-10,000 people in the U.S. are hospitalized annually from Legionnaires’ outbreaks, and about 100,000 cases occur each year. See id. Many people who contracted the illness have since sought to hold a party legally responsible for their illnesses. In such cases, plaintiffs have often eschewed a strict liability theory to prove a defendant’s liability in favor of making “a negligence claim under a premises liability theory, asserting that a defendant ‘owed a duty to inspect, maintain, repair, operate and test the water system in the premises, including the faucets, showers, pool and hot tub or spa, in a reasonable and prudent manner and with due regard for the health and safety of invitees,’ or more generally, that a defendant ‘owed a duty to exercise reasonable care in the maintenance of the premises and operation of its systems in a reasonably safe manner so as to not subject invitees to an unreasonable risk.’” Id.

Plaintiffs have sought to hold many parties accountable for Legionnaires’ outbreaks, from building owners to architects and engineers. In fact, parties “involved with the ownership, operation, management, and maintenance of hotels, hospitals, senior housing facilities, and condominiums have increasingly been targeted in such lawsuits.” Id. Even cruise ship owners and operators are not immune from lawsuits on these grounds. The sheer number of possible defendants means that expert witnesses are needed in nearly every field that may factor into a premises liability tort based on a Legionnaires’ infection. As two legal analysts explain, “Persons or entities responsible for the development, design, engineering, construction, manufacture, installation, maintenance, and repair of the structures or building systems identified as the source of an outbreak also have potential legal liability.” Id.

Whenever such a large and varied group of people may be the subject of toxic tort litigation, expert witnesses will be needed in each field to allege and respond to claims as to the source of a specific Legionnaires’ outbreak. Infectious disease specialists, doctors, construction experts, environmental, water safety, and public health experts are just a few of the kinds of consultants and testifying witnesses who will be needed to make or break such cases. Given the scope of potential defendants, parties who may be involved in any phase of the ownership, development, operation, or maintenance of a given structure or building should retain experts as early as possible to obtain a credible opinion on whether or not each party should bear legal liability.

In addition to the need for various experts to assist with the diverse type and quantity of prospective defendants, other legal issues surrounding Legionnaires’ infections will require expert witnesses. For example, in many cases, each party must seek to establish what the standard of care should have been for a particular party and whether that standard was violated. To wit, “Common theories of negligence include failure to maintain water distribution systems properly to prevent the growth of Legionella; failure to set and maintain hot water storage temperatures in a range sufficient to eliminate or control the growth of the bacteria; failure to ensure proper chlorination of a water supply; failure to periodically flush water systems to eliminate sediment and other contaminants; and failure to maintain proper water flow throughout a potable water system.” Id. Accordingly, experts will be required for several purposes: to determine water safety matters and provide specialized opinions on the source of a particular infection, to determine if certain sewage and environmental waste matters were handled appropriately, and to establish a link between a “plaintiff’s onset of disease and the defendant’s premises.” Id.


A final reason why expert witnesses are of such import in Legionnaires’ litigation is that “Currently, there are no federal, state or local statutes, codes, or regulations that establish a duty of care specific to the control of Legionellae for any structure or industry outside of healthcare.” Id. The lack of a clear government guideline or mandate leaves the issue of the standard of care to the Legionnaires disease expert witnesses. Each party will be required to advance or defend against a claim by utilizing witnesses with specialized knowledge of the typical duties involved in a particular setting. Because a determination of the scope of a particular duty involves several different inquiries, many different experts will be required to prove different parts of these claims. Issues such as whether a risk was foreseeable will require the testimony of persons with specialized knowledge of customary practices in a particular field.


By: Kat S. Hatziavramidis, Attorney-at-Law