California’s Proposition 65 requires warnings labels on products that may contain chemicals known to the state to cause cancer, birth defects or reproductive issues. That includes everything from protein powder to e-cigarettes to wood furniture. Luckily, most foods with warnings are still safe to eat but continue to steer clear of products high in mercury and lead. 

What is Prop 65?

Order from almost any restaurant with a deep fryer or coffee machine in California, and you’ll likely be greeted by a sign warning you that whatever you’re about to consume could give you cancer. Businesses including Starbucks, bodegas, and grocery stores are littered with the warnings, mandated by the state in efforts to inform consumers about the chemicals hiding in their cup of coffee or box of cereal.

California is the only state that labels products that contain potential carcinogens under a controversial measure called Proposition 65. Originally passed in 1986 as the “Safe Drinking Water and Toxic Enforcement Act,” Proposition 65 identifies potentially toxic chemicals lurking in household products, foods, and the environment, and it incentivizes businesses to reduce their use of the harmful toxins.

The law has caught a lot of backlash for its broad warnings and minimal levels of detection that require labeling. Proponents say it’s proactive, urging consumers to phase out foods and products that may prove cancerous to humans ahead of long-term studies.

Detractors call the proposition confusing, as some chemicals labeled as carcinogens are found in many perfectly healthy foods such as almonds, tuna, and spinach.

The proposal requires the state to label products that contain chemicals known to cause cancer, birth defects or reproductive harm. Up until an amendment passed in August 2016, those warnings were only required to state the presence of a potentially toxic chemical without identifying it or explaining the effects of its exposure.

But, under the new regulations, which went into effect August 30, 2018, the Office of Environmental Health Hazard Assessment (OEHHA) increased labeling and changed the warning’s verbiage, explicitly naming the chemicals a product “can expose” users to. Updated labels also bear a yellow warning symbol.  

How Did Healthy Foods Become Prop 65?

Some products are obvious Prop 65 culprits, like fried foods. In particular, carbohydrates that form the carcinogen "acrylamide" and alcohol both receive Prop 65 labels because they can cause birth defects when consumed by pregnant women.

But unexpected foods often bear the warnings too, like canned sweet potatoes, nuts and, perhaps most controversially, coffee.

“I think that information is typically always a good thing, but I think what [the proposition] lacks is nuance,” says Matthew Pratt, Ph.D., associate professor of chemistry and principal investigator at the Pratt Lab at the University of Southern California.

Think of it this way. If you were to step into Pratt’s lab, every chemical bears a warning label, and that’s a good thing, he says. In a lab, the warning is because exposure to large quantities of the toxins can cause harm when mishandled.

But, the concentrations of those same chemicals in foods and household products are “vanishingly small,” he says, so the warnings, while well-intentioned, are more informative than definitive.

Everything from the chemicals used in dental procedures and furniture manufacturing to bread crusts and prune juice is subject to the proposition’s wide rulings.

Even more confusing, many of the 900-plus chemicals on the Prop 65 label list are only cancerous in the results of animal studies performed with much higher concentrations than what you find in foods, while human studies of the carcinogens in foods have largely proven inconclusive or completely safe.

Since the law was enacted, the state has fought claims that Prop. 65 is misleading, a criticism even the Food and Drug Administration publicly acknowledged.

One day before the new amendment’s warnings went into effect, FDA commissioner Scott Gottlieb supported a proposal that would exempt coffee from warnings, citing a World Health Organization study that found no irrefutable evidence that drinking coffee causes cancer.

“There’s nothing incorrect about saying acrylamide is toxic, but there’s also no direct evidence that trace amounts in coffee pose any sort of risk,” Pratt says.

The OEHHA may even label plant-based protein powder and baby foods if they contain ingredients like spinach or carrots grown in soil, whether the metals occurred naturally or as a result of environmental contamination. A 2017 Environmental Defense Fund analysis over 11 years found lead in 86 percent of baby foods containing sweet potatoes and 89 percent of children’s grape juice. 

What to Do About Prop 65

The good news: Diet essentials like nuts, leafy greens, and (yes!) coffee contain such a minute concentration of Prop. 65 chemicals that they’re safe for consumption. The OEHHA still recommends fish as a healthy source of protein and fat, as long as it’s a variety low in mercury like salmon and tilapia.

Protein powders are safe, too, as long as recommended serving sizes are followed and you find a powder that is NSF Certified for Sport, which ensures that there are no dangerous levels of toxins or metals. (All Ladder products are NSF Certified for Sport.)

Pratt recommends continuing to avoid fried food for its negative impact on cholesterol and blood pressure and high trans fat and sodium content, even if research on the relationship between French fries and cancer is lacking, as well as products high in mercury, like certain fish, dental amalgam fillings and some skin creams. Lead, still found in some toys, ceramic dishes and purses, among others, also adversely impacts children’s developing brains, he says.