Red Dye No. 40, a synthetic food dye that's used to achieve a bright crimson color in condiments and candy alike, has been a hot topic among policy makers and food safety advocates in the U.S.
While there are thousands of chemicals allowed for use in our country's commercial food system, many of those that have been reviewed by the U.S. Food and Drug Administration have not been reevaluated for decades. Red 40, for example, was first registered with the FDA in 1971 and last evaluated for health risks by the Environmental Protection Agency in 2014.
The artificial coloring that's synthesized from petroleum, also known as Allura Red AC, is one of the nine "Trusted Source" certified color additives the FDA approves for use in foods and beverages.
In processing the color, according to the FDA, the dye is combined with aluminum to create Red 40 Lake, which is not water soluble in order to prevent colors from bleeding in products like chewing gum.
During the Red 40 production process, per the FDA, each batch gets screened for purity certification and possible contaminants.
According to the Department of Agriculture's branded foods database, Red 40 is the most used per pound consumed among three food dyes found in over 36,000 food products sold in the U.S.
Some studies have shown Red 40 is a carcinogen in animals.
"Scientific studies have suggested a potential link between Red Dye 40 and hyperactivity, including ADHD and report noted improvements in behavior and attention when such dyes are eliminated from diets," Kantha Shelke, PhD, founder of food science research firm Corvus Blue and member of the Institute of Food Technologists, told ABC News.
The debate over processed foods and synthetic food dyes has had a resurgence in America, in large part as a result of heated criticism from Robert F. Kennedy Jr., who President-elect Donald Trump has said would lead the Department of Health and Human Services in his new administration. Kennedy has voiced his intent to "Make America Healthy Again" if confirmed as HHS secretary, including cracking down on ultra-processed foods, many of which contain additives.
Like most issues related to commercially processed food and the potential health impacts, there is more research that needs be done to hone in on what and how much of something could be considered unsafe to eat.
At the Senate Health, Education, Labor and Pensions Committee meeting earlier this month, agency heads delivered blunt assessments of America's obesity problem and consumption of ultra-processed foods and chemicals in our food supply.
The outgoing FDA chief, Dr. Robert Califf, and his deputy commissioner for human foods, Jim Jones, said there's no legal path forward in banning these substances, such as Red 40 that hasn't been reevaluated in decades, without proper funding for scientific evidence.
Califf and Jones offered Red No. 3, another color additive made from petroleum that gives drinks and foods a cherry-red color, as an example of forward progress.
"With Red 3, we have a petition in front of us to revoke the authorization board, and we're hopeful that in the next few weeks, we'll be acting on that petition," Jones told lawmakers of the juxtaposition for the similar substance used in foods.
Red No. 3 has been shown to cause cancer in laboratory animals, but many scientists do not believe the substance triggers the same "mechanism of carcinogenicity" when ingested by humans, Jones told the Senate panel.
Shelke said that "evidence of the carcinogenicity of large doses of Red 3 in laboratory animals has been available since the 1980s," and noted that the "FDA banned Red 3 in cosmetics" in 1990," but 34 years later is still in the process of developing a new framework for post-market assessments of chemicals in food."
Under current U.S. law, the FDA cannot ban Red No. 3 while scientists try to determine with certainty that it is safe for humans, it would take Congress to change that.
But the task to correct course in food regulation is not impossible as increased public concern has driven recent legislation.
By the end of 2027, food served in California public schools must no longer include any product that contains artificial food colors -- including Red 40 -- thanks to a landmark bill that Gov. Gavin Newsom signed into law earlier this year.
"Historically, the FDA has been reactive, addressing public health concerns only after external pressure in the form of petitions, lawsuits, or state-level bans," Shelke told ABC News. "The FDA’s potential move to ban artificial food dyes may gain momentum as lawmakers in 10 states follow California’s lead by introducing similar legislation."
The EPA and WHO list Red 40 as "low concern" and note that most people don’t typically take in enough of it to cause a problem.
However, the European Union requires a warning label on products that contain Red Dye 40 that reads, "may have an adverse effect on activity and attention in children."