Don't use decorative napkins to rest your utensils — some contain carcinogens

Many diners place a napkin on the restaurant table and rest their utensils on top, treating it as a small act of hygiene etiquette. But researchers are warning that some napkins require caution.

A study published in the 2026 edition of the Korean Journal of Food and Health Safety by researchers at the Seoul Metropolitan Government's Institute of Public Health and Environment found that carcinogenic substances were repeatedly detected in some commercially available paper napkins.

The researchers tested 105 types of napkins in total — 21 types of domestically distributed disposable paper napkins classified as hygiene products, and 84 types of imported decorative napkins classified as general consumer goods — checking for harmful substances including formaldehyde, optical brightening agents and benzophenone.

The results differed sharply by product category. The 21 types of domestic disposable napkins, regulated as hygiene products, showed no detectable levels of any of the three substances.

By contrast, among the 84 types of imported decorative napkins classified as general consumer goods, formaldehyde was detected in eight types, optical brightening agents in 14 types, and benzophenone in 23 types.

Benzophenone, a carcinogenic substance that can remain in printing ink, was found in 23 products at levels ranging from 0.003 to 0.022 mg/L. Formaldehyde — classified as a Group 1 carcinogen by the International Agency for Research on Cancer — was detected in eight products at levels between 0.053 and 0.162 mg/L.

Optical brightening agents are used to make paper appear whiter. Direct skin contact can cause itching, allergic reactions and respiratory irritation, and prolonged accumulation in large amounts may lead to gastrointestinal disorders.

What matters most, however, is the actual level of exposure.

When the researchers assessed risk based on a scenario of using one napkin per day from the product with the highest benzophenone detection, estimated exposure came to about 0.31 percent of the tolerable daily intake. Under a scenario assuming direct food contact — similar to food packaging — the figure dropped to about 0.01 percent.

Plain disposable paper napkins commonly provided at restaurants in South Korea are regulated as hygiene products and subject to self-quality inspections and regular testing. For hygiene products such as tissue paper, formaldehyde levels must remain below 4 parts per million; for children's diapers, the limit is 20 ppm.

Decorative napkins classified as general consumer goods, however, are subject to no such standards.

For that reason, the Seoul Metropolitan Government's Institute of Public Health and Environment recommended that decorative napkins not be used to wipe the mouth or hands, or placed in direct contact with food.

In addition, using a regulated disposable napkin or a dedicated utensil rest can help keep cutlery off the table surface.

More important still is washing hands before eating. Even if the table and utensils look clean, microorganisms on the hands can transfer to the mouth during a meal.