The Law of Scent: Smells in Unexpected Places

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By Professor Victoria Sutton

September 15, 2024

Guest Opinion. The sense of smell, considered to be one of the most evocative of the human senses, finds itself in perhaps unexpected places in the law.

Capturing and communicating a “scent” still eludes the digital technology behemoth and social media machine where many humans spend a good part of their day and often most of their social life. One has to wonder what is lost in our life in cyberspace without the use of our sense of smell?

The elusive nature of scent can be endearing. It is connected to a time and place. The scent of baking bread or a rose typically trigger happy reactions. Smells can also trigger rage. In one case, I remember a detective asking the man who murdered his wife while she was cooking chicken livers for him, why did he murder her? “I told her I didn’t want any more chicken livers,” he said. Clearly, his rage was triggered by the smell of cooking chicken livers, shocking as that may be.

Industries are built around “scent,” one of our five senses that tell us about the world around us. The perfume industry, the cleaning industry, and the food scents businesses are but some examples. We add scent to crayons, scratch-and-sniff cards, homes, cars, hotel lobbies, elevators and just about anything. Humans have memories based on scents, recognize scents, and use scents to attract mates or to cover up crime scenes.

Dogs are much better at smelling than we are. They can smell about 100,000 times more than we can. They can sniff out one molecule in a million, or equivalent to one teaspoon in two olympic size swimming pools. They can track a smell up to a mile or so away. They serve as police dogs and military dogs sniffing out the bad guys and discovering contraband, the enemy, criminal evidence and dead bodies, both above and below ground.

There are trained pigs that find truffles (fungus) that are living underground in the roots of oak trees in the pastoral lands of France (and other places) to service the gourmet food industry.

The Law of Scent

Municipalities lead the way in regulating obnoxious or harmful smells, because they have jurisdiction over property use and so this is connected to the smells these uses emit. They act with the power given them by the state. Sometimes it is state law that regulates smell.

In tort law, “nuisance” is an act that unlawfully interferes with the use or enjoyment of land or property. Nuisances can be either public or private, and unpleasant or harmful odors can be both public and private nuisances.

The Right to Farm Act state laws were inspired by those who complained about the stench of cattle manure after moving near cattle feeding operations or hog lots or other smelly farming operations. Coming to the nuisance, is the legal term that describes a situation where you knew you were moving to the nuisance (bad smells) and so you cannot now try to complain and close the business that was there before you were. The Right to Farm Act precludes those causes of action for public or private nuisance and all fifty states have some form of this law. However, in McKiver v. Murphy-Brown, LLC, the court upheld a jury verdict awarding damages to neighbors of a hog farm, where the odor was deemed an unreasonable interference with the plaintiffs' use and enjoyment of their property.

Scent as a Trademark

Trademarks serve as identifiers of the source of goods or services, traditionally relying on visual and verbal cues like logos, words, or symbols. However, the concept of a trademark extends beyond these forms and may include non-traditional marks, such as scents. The Lanham Act, which governs trademarks in the United States, does not explicitly exclude scents from trademark protection. In fact, the United States Patent and Trademark Office (USPTO) has granted trademark registrations for certain scents that have acquired distinctiveness and are non-functional.

The most notable case is the registration of a "scent of plumeria blossoms" for sewing thread and embroidery yarn by the USPTO. The scent is considered a "source identifier," signaling to consumers that the product comes from a specific manufacturer. However, to obtain trademark protection for a scent, the applicant must demonstrate that the scent is distinctive and not essential to the product's function. For instance, the scent of a rose for a rose-scented perfume would not qualify, as the scent is functional—consumers expect a rose scent from a rose perfume.

The concept of scent trademarks remains controversial, where care not to make protections so broad that others cannot fairly use the scent when needed.

Scent in Criminal Law and Evidence

Scent plays an often understated role in criminal law, particularly in the context of evidence. Scent evidence can be used in criminal investigations and trials, most commonly through the use of "scent lineups." These lineups involve trained canines, often referred to as "scent dogs," who are employed to detect a suspect's scent from a lineup of scent samples. The dogs are trained to follow the unique scent markers that every individual possesses, which are considered distinct enough to serve as identifying characteristics.

Defense teams will often question the reliability of canine olfaction, the training and handling of dogs, and the procedures used in collecting and preserving scent samples. After the U.S. Supreme Court held that infrared heat detectors could not be used to detect heat coming from a marijuana-growing building without a warrant because it was not technology generally available to the public, and so not a legal search, a challenge to sniffing dogs was brought. Sniffing dogs are not technology generally available to the public (these dogs are highly trained and valued at nearly $100,000 and are usually owned by law enforcement agencies). So when a challenge was brought that sniffing dogs could not be used without a warrant, the court drew the line, excluding sniffing dogs from that test.

Are sniffing dogs “technology” or are they enhancements of human sense of smell?

In Florida v. Harris, the U.S. Supreme Court held that the alert of a well-trained and certified drug detection dog is sufficient to establish probable cause for a search and there is no requirement to prove the dog’s reliability each time.

Scent as an Indicator of Discrimination or Disability

Scent also intersects with laws related to discrimination and disability. Under the Americans with Disabilities Act (ADA), individuals with chemical sensitivities or "multiple chemical sensitivity" (MCS) may be entitled to reasonable accommodations in public places and employment settings (42 U.S.C. § 12101). For example, if an individual with MCS experiences adverse reactions to certain fragrances, an employer may need to provide a fragrance-free environment as a reasonable accommodation, provided it does not impose an undue hardship on the employer.

Similarly, Title VII of the Civil Rights Act of 1964 protects employees from discrimination based on religion, which may include scent-based practices. For example, an employee who wears a specific fragrance as part of religious observance may be entitled to reasonable accommodation, such as being permitted to wear the fragrance despite a general workplace policy against scents (42 U.S.C. § 2000e).

Scent, Indigenous Religious Practices and Rules

The use of sage, sweetgrass and cedar are central to ceremonies and traditional practices and is so common across tribal communities that it is often used in intertribal meetings, powwows, and other ceremonies. Sage is particularly used for cleansing ceremonies and so it is understandable that it would be used in common areas on campus, for example. The curling smoke from burning sage is the rising of spiritual prayers to the sky, and the pungent aroma of sage is shared by everyone in that space.

The University of North Dakota has a very detailed policy for the use of sage, sweetgrass and cedar for residential housing common areas. They use time, place and manner criteria in First Amendment, Freedom of Expression tests to allow its use, thereby avoiding the infringement on the rights of others — not to smell it. The general policy reads:

Use of Sage, Sweetgrass, and Cedar in Residence Halls In support of the spiritual lives of American Indian/Alaska natives, UND Housing Policies allow the spiritual use of sage, sweetgrass, and cedar smoke, when its use is for the purpose of purification and prayer; is consistent with time-honored cultural, traditional, and spiritual observances; and complies with the protocols outlined in this document.¹¹

Scent, Technology and Law

Courts and legal scholars continue to consider how to effectively balance the subjective nature of olfaction with the need for objective legal standards. Increasing reliance on technology like olfactometers—devices that measure the intensity of odors—or standardized guidelines for scent collection and analysis in forensic contexts.

Patents and recent patent applications demonstrate the quest to harness the power of scent. U.S. Patent No. 7,203,417 is a portable scent delivery device that selectively releases smells, preferably through a headset or a mobile telephone. The scent travels to the user's nose by diffusion.

Sony also filed for a patent, to “Overlay Non-Video Content on a Mobile Device”, U.S. Patent No. 12/554,958 in 2013. This invention injects scent technology into video games, so that the user can smell what the video character smells in real time in the movie or video game.

These technological ways of transmitting scent could find themselves into evidence in the courtroom like a video depicts the recreation of an accident.

Conclusion

While scent may not be the first thing that comes to mind when considering legal issues, it is undeniably relevant across various areas of law. From trademarks and criminal evidence to nuisance law and anti-discrimination protections, scent is a part of the law.

In the end, it is a quest of balancing this subjective human experiences with objective legal standards.

To read more articles by Professor Sutton go to:  https://profvictoria.substack.com/ 

Professor Victoria Sutton (Lumbee) is a law professor on the faculty of Texas Tech University. In 2005, Sutton became a founding member of the National Congress of American Indians, Policy Advisory Board to the NCAI Policy Center, positioning the Native American community to act and lead on policy issues affecting Indigenous communities in the United States.