Manufacturers and industrial operators are often asked to balance providing meaningful warnings with the risks associated with over-warning.

By James H. Keale, Timothy R. Freeman, Joseph B. Sala, Ph.D, and Rachel Kelly

In the wake of an accident, adverse effect, or misuse involving a product, a lawsuit will often be filed and an expert witness will emerge and argue that additional, more specific, or different warnings would have altered the injured plaintiff’s understanding or interpretation of the risks associated with the product and changed his/her behavior to avoid the injury. The expert will typically claim that the warnings provided by the manufacturer were deficient because they did not address the particular scenario that resulted in the injury.

Product liability attorneys have seen this dynamic play out countless times, illustrating the fundamental tension between manufacturers’ legal duties to warn about the foreseeable risks inherent in the use of their products and the impracticality, and scientifically unsound nature, of attempting to warn about all conceivable scenarios where an accident or adverse event could occur. In most states, manufacturers have a legal duty to warn of the risks based on “foreseeable uses” of their products. So how can manufacturers best protect their customers, end users, and themselves? After all, manufacturers are not insurers of their products; their duty is to create and distribute reasonably safe products.

Using the science behind the human response to warnings and instructions, as well as case law addressing failure to warn claims, it is apparent that there is a fundamental soundness to designing direct, concise, and uncomplicated warnings. Using this framework, this article explores the duties of manufacturers with respect to warning content, when warnings are required, and the potential dangers and impracticality associated with “over-warning.”

Product Liability Litigation Illustrates The Fundamental Difficulties Related To Manufacturers Legal Duties Product Safety Photo 1, Industry Today
Product liability litigation illustrates the fundamental difficulties related to a manufacturers’ legal duties to warn about risks.


While product liability laws in every state differ in some respects, the general obligations of manufacturers are similar. In general, the inquiry in a warning defect case focuses on the likelihood of risk and the adequacy and effectiveness of warnings. Manufacturers have a duty to warn and instruct end users regarding potential dangers and proper use of a product, while taking into account assumed knowledge that the intended users should have. This includes a duty to warn of unintended uses that are “reasonably foreseeable.”

An adequate warning typically includes all relevant information essential to make use of the product safe. A warning should contain information sufficient to inform an individual about  potential hazards and the opportunity to change behavior to prevent undesirable consequences. However, a warning is unlikely to be effective unless the end user meets a number of additional conditions. These include, at a minimum, reading the warning, understanding the information, and subsequently changing behavior in order to comply with the warning.

Regardless of whether a warning is adequate as a matter of law, individualized factors determine if it is read and followed. Science and research demonstrate that, irrespective of a warning’s content or format, whether a person notices a warning is dependent upon whether or not the individual is seeking warning information and attends to the warning. Often, warnings will go unnoticed despite design elements intended to “capture a user’s attention.” Numerous other individualized factors can also affect compliance with warnings, including a person’s familiarity with a product and the amount of effort required for “cost of compliance” to follow the warning.


Deciding when to warn should be based on careful consideration of the likely effectiveness (behavioral change) and potential impact of the warning (risk reduction). Not all potential hazards require a warning, nor is it advisable or productive to attempt to warn of every potential hazard. In most jurisdictions, manufacturers do not have a duty to warn of obvious hazards that are so basic to the function or purpose of the product that a warning would serve no useful purpose. For example, there is no duty to warn that matches burn or that knives are sharp.

Nevertheless, defining an “open and obvious danger” can be daunting. Experts who are quick to identify dangers for which they claim more specific warnings are required may also be quick to distance themselves from the industry-accepted understanding of those dangers. Recommendations from the scientific community and voluntary standards offering guidance on the presentation of warnings and safety information are also important considerations. For example, scientific research on warnings has established that when a product or environment includes obvious hazards, a warning is not required.

Manufacturers may need to design specific warnings related to unobvious hazards while relying on more general safety information to address obvious hazards. Manufacturers must, to some degree, rely on end users to use the information provided to them and the context of the product’s use to avoid hazards. It is neither practical nor productive for manufacturers to attempt to create an explicit, exhaustive list of situations to “warn against.” Nevertheless, as any experienced product liability attorney can attest, the open and obvious nature of a hazard does not preclude accidents or litigation.  


End users often have confidence that they understand the hazards and rules for use of products that they have experience using, so they tend to not read or heed warnings that are provided. This dynamic can be particularly pronounced in the context of products where the typical operators have extensive experience, exposure, and familiarity with the product. Warnings provided with such products are often ignored.

Many courts, as well as regulatory agencies, have highlighted concerns and recognized the dangers inherent in “over-warning.” Negative effects can arise when a person’s cognitive and information processing capacity is overloaded by too much safety information, limiting attention to individual messages within warnings, reducing the overall credibility of warnings, and reducing the ability to determine relative magnitude of risks. Scientific research and governmental agencies have advised manufacturers that “over-warning” weakens the effectiveness of more significant information presented and can nullify warnings provided, due to the resulting inattention of the reader. This is particularly impactful in the scenario of warnings addressing highly unlikely or theoretical hazards, which often causes warnings to be seen as “false alarms.”

Requiring too many warnings trivializes and undermines the purpose of warnings and can effectively minimize important warnings addressing the severe and unobvious dangers that end users should consider. Thus, manufacturers often have good reasons for not providing overly detailed warning labels and for not attaching all warning labels directly to their products.


Decisions addressing how to effectively communicate warnings and safety information must be made whenever a hazard is associated with a product. Unfortunately, often there are not predetermined rules that clearly define which warnings need to be present and which are superfluous. Hence, a battle over which warnings are appropriate, adequate, and reasonable will forever play out in courtrooms whenever there is an accident involving a product. It is clear, however, that the solution is not for manufacturers to attempt to provide complex and exhaustive lists of warnings and safety information.

Attempting to address every possible injury scenario with a warning does not enhance overall product safety, given what we know from science regarding the human response to warnings. It is not easy for manufacturers to simultaneously provide warnings that meaningfully increase safety, avoid risks associated with “over-warning,” and minimize liability in potential litigation. There is a balance that needs be struck between the provision of sufficient detail and information to promote safety and hazard avoidance without creating a litany of highly specific, complex, and inaccessible directives. While there is no way to completely avoid liability and protect all end users in every possible scenario, “simple and concise” as opposed to “detailed and exhaustive” warnings are more appropriate to address safety concerns and to persuade juries that the warnings and safety information provided are reasonable.

JamesKeale Tanenbaum Keale Llp, Industry Today
James H. Keale

James H. Keale is a partner and president of Tanenbaum Keale LLP. His practice focuses on defending manufacturers from a variety of industries in the areas of product liability, personal injury, commercial and specialty and catastrophic tort litigation. He can be reached at

TimothyFreeman Tanenbaum Keale Llp, Industry Today
Timothy R. Freeman

Timothy R. Freeman, an attorney at Tanenbaum Keale LLP, also contributed to this article. He focuses his practice in the areas of product liability and catastrophic personal injury. He can be reached at

Joe Sala Exponent, Industry Today
Joseph B. Sala, Ph.D.

Joseph B. Sala, Ph.D. is Vice President and Principal Scientist for Exponent, a multi-disciplinary engineering and scientific consulting firm. His work focuses on the cognitive, perceptual, physical, and developmental human factors issues relating to accidents and injuries. He can be reached at

Rachel Kelly Exponent, Industry Today
Rachel Kelly, Ph.D.

Rachel Kelly, Ph.D. is a Managing Scientist at Exponent. Her focus is on physiological, cognitive, and perceptual issues relating to human behavior. She can be reached at

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