Because of its Near Ubiquity in Food, California Must Set a Realistic Safe Harbor Level for Furfuryl
Updated: Feb 4, 2022
California has extended the comment period for the common food ingredient, furfuryl alcohol, for listing as a carcinogen under Proposition 65 (Prop. 65); comments are now due at the end of September. Under the Act (Prop. 65), if (1) an “Authoritative Body” has deemed a substance carcinogenic and (2) the evidence considered by the authoritative body meets the sufficiency criteria contained in the regulations, the substance is included in the Prop. 65 list.
According to California’s Office of Environmental Health Hazard Assessment (OEHHA), the “US EPA concluded that furfuryl alcohol is ‘Likely to be Carcinogenic to Humans’”. “Evidence described in the report includes studies showing that furfuryl alcohol increases the incidence of rare nasal epithelial squamous cell carcinomas and combined nasal epithelial carcinomas and epithelial squamous cell carcinomas in male rats, and rare renal carcinomas and combined carcinomas and adenomas in male mice.” However, even though furfuryl alcohol proved to be carcinogenic in two different species of rodents in a two year study, the study was performed using inhalation, rather than oral exposure. Therefore, the results may not be particularly relevant for furfuryl alcohol exposure from food.
According to the National Toxicology Program (NTP) “[F]uran, furfural and furfuryl alcohol are commercially important compounds which are produced in large quantities [and an important reason why it was selected from testing] and have many industrial applications. Furfuryl alcohol is used in numerous industrial and manufacturing processes with considerable potential for occupational exposure. Occupations with the greatest number of exposed workers include carpentry, tile setting, and metal molding and casting, in which workers are exposed through the use of grouts, mortars, and furan resin sand containing furfuryl alcohol-based resins, and packaging and filling machine operations, from which workers are exposed to furfuryl alcohol in solvents.” As a result of these occupational exposures, furfuryl is regulated as an air contaminant by the Occupational Safety and Health Administration.
Although humans may be exposed to furfuryl alcohol via industrial applications, a much wider human population is exposed to furfuryl alcohol in food. Furfuryl alcohol in food is either naturally present or present as the result of an act of man such as in the baking of bread or roasting of coffee, which produces furfuryl alcohol as the result of the Maillard reaction. Furfuryl alcohol has been found both as naturally present and as an act of man in wheat and white bread, crispbread, coffee, black tea, microbial fermented tea, soybean, fresh plum, heated beans, rice bran, quince, malt, peated malt, Bourbon vanilla, wild rice, fermented shrimp, roasted almonds, cooked apple, apple juice, roasted barley, beans, beef fat, canned beef stew, beer, brandy, cocoa, cocoa beans, coffee, roasted coffee, roasted filberts, honey, heated skim milk, dried mushrooms, roasted onion, yellow passion fruit, roasted peanuts, pineapple, popcorn, potato chips, roasted sesame seeds and other foods. While occurring naturally in some foods and thus available for the naturally-occurring exemption (or “safe harbor”), that which is the result of an act of man is not eligible for the naturally occurring safe harbor.
As an added food ingredient, furfuryl alcohol (often made from roasted corn cobs or sugar cane bagasse) is used as a flavoring agent to contribute brown, subtly smoky notes to Indonesian-type vanilla flavors, bacon and other smoked meats, lapsang souchong tea, whiskey, grain, coffee and barbecue flavors.
Our hope is that when California’s OEHHA considers listing furfuryl alcohol as a Prop. 65 substance, it will recognize that the carcinogenicity studies were inhalation studies, which produced what OEHHA itself describes as “rare” tumors, and that, although a limited number of humans are exposed to furfuryl alcohol occupationally, furfuryl alcohol is a common constituent of food. The safe harbor level for furfuryl alcohol in food should be set commensurately high.
 US Environmental Protection Agency (US EPA, 2014). Cancer Assessment Document, Evaluation of the Carcinogenic Potential of Furfural and Furfuryl Alcohol. Final Report. Health Effects Division, Office of Pesticide Programs. February 6, 2014.
 G.A. Burdock. (1997) Encyclopedia of Food and Color Additives. Volumes I-III. CRC Press, Boca Raton, FL. 3153 pp
 Judith Michalski et al. Perfum. Flavor. 39(2), 48-49, (2014)