Outgoing US President Joe Biden’s administration on Wednesday announced a ban on Red Dye No 3, a controversial food and drug coloring long known to cause cancer in animals.

Decades after scientific evidence first raised alarm, Red 3, as it is also called, is currently used in nearly 3,000 food products in the United States, according to the nonprofit Environmental Working Group.

“FDA is revoking the authorized uses in food and ingested drugs of FD&C Red No 3 in the color additive regulations,” said a document from the Department of Health and Human Services, published in the Federal Register on Wednesday.

The decision stems from a petition filed in November 2022 by the Center for Science in the Public Interest (CSPI) and other advocacy groups, which cited the “Delaney Clause” – a provision mandating the prohibition of any color additive shown to cause cancer in humans or animals.

Notably, the FDA determined as early as 1990 that Red 3, whose chemical name is erythrosine, should be banned in cosmetics because of its link to thyroid cancer in male rats.

However, the additive continued to be used in foods, largely due to resistance from the food industry. Manufacturers of maraschino cherries, for example, relied on Red 3 to maintain the iconic red hue of their products.

It’s also present in thousands of candies, snacks and fruit products – and thousands of medicines, according to a search of a government-run database, DailyMed.

“Manufacturers who use FD&C Red No 3 in food and ingested drugs will have until January 15, 2027, or January 18, 2028, respectively, to reformulate their product,” the FDA said.

Although the agency acknowledged a cancer link in rats, it maintained that the available evidence does not support such a link in humans, citing differences in hormonal mechanisms between the species and significantly lower exposure levels in people.

While the FDA determination focused on carcinogenicity, other research has also found potential neurobehavioral effects of synthetic food dyes on children, notably Attention-Deficit/Hyperactivity Disorder (ADHD).

Animal studies indicated that synthetic food dyes caused changes in neurotransmitter systems in the brain and produced microscopic changes in brain structure, affecting activity, memory and learning.

The United States has been slow to act on Red 3 compared to other major economies. The European Union banned its use in 1994, with similar prohibitions enacted in Japan, China, the UK, Australia, and New Zealand.

Carl Tobias, a former FDA legal consultant and now a professor at the University of Richmond, told AFP it was “hard to square” the agency’s mission of protecting American health with the prolonged delay in reaching the decision. “There’s pretty extensive lobbying, there always has been, and some of it is sometimes effective,” he said, calling the ban a “step in the right direction.”

CSPI also hailed the FDA’s decision as long overdue, and expressed hope that it would pave the way for broader action on other harmful chemicals in food. “They don’t add any nutritional value, they don’t preserve the food – they’re just there to make food look pretty,” Thomas Galligan, a scientist with CSPI, told AFP.