Introduction to Prop 65
As a cancer dietitian, I know many of you are particularly careful with your food and product choices, and you may be familiar with California’s Proposition 65 (Prop 65). Perhaps you’ve seen this label: “This product is known to the State of California to cause cancer, birth defects, or reproductive harm.” YIKES! Reading that can be terrifying, especially for survivors who have gone through treatment and are trying to live a cancer prevention lifestyle. Let’s take a closer look at Prop 65, its goals, and why it might be causing more stress than necessary.
What is Prop 65?
Prop 65, also known as the Safe Drinking Water and Toxic Enforcement Act, was initially passed in 1986. Its original purpose was to protect drinking water from toxic chemicals. Over time, it expanded to include consumer products, requiring businesses with ten or more employees to label products containing certain chemicals as potentially hazardous to human health. Today, the list includes over 900 chemicals that California considers potentially harmful.
Common foods and items that have the prop 65 warning include but are not limited to the following:
- french fries and potato chips.
- fried/baked snack foods
- roasted asparagus
- canned sweet potatoes and pumpkin
- canned black olives
- roasted nuts
- roasted grain-based coffee substitutes
- prune juice
- bread crusts and toast
- certain breakfast cereals
- Crackers
- Cookies
- Alcoholic beverages
- King mackerel
- Shark
- tilefish
- Swordfish
- Marlin
- bigeye tuna
- Furniture
- Cleaning products
- Window coverings
- Diesel engine exhaust: Diesel engine exhaust
How Prop 65 Labels Might Be Misleading
On the surface, Prop 65 appears to protect consumers, but many scientists argue it causes more confusion and fear than clarity. Here’s why: Prop 65 doesn’t consider the exposure level or dosage of chemicals when labeling them as dangerous. In other words, the law does not differentiate between minimal and high exposure. This is a problem because any substance can be harmful in a large enough dose. Even something as essential as water can cause harm if over consumed!
When it comes to chemicals, the dose makes the poison. Just because a product contains a chemical on the Prop 65 list doesn’t mean it’s harmful at the level in that product. Unfortunately, the labeling doesn’t provide this context, leading many consumers—especially cancer survivors—to worry about the safety of everyday items.
How Are Chemicals Added to the Prop 65 List?
Every year, a committee in California, made up of experts in various fields, reviews chemicals to determine which should be added to the Prop 65 list. While this might sound thorough, a large amount of the evidence used comes from animal studies at extremely high doses or in vitro studies (in lab dishes, not human studies).
Although the International Agency for Research on Cancer (IARC) is often referenced for Prop 65, IARC studies tend to classify chemicals very broadly. For example:
- Possibly Carcinogenic means there’s limited evidence of potential harm.
- Probably Carcinogenic means there’s strong but not conclusive evidence of harm.
- Carcinogenic means there is enough evidence to indicate a chemical may be harmful. However, even a substance classified as a “carcinogen” does not always cause cancer in humans.
The IARC’s cautious approach is helpful for certain regulations but can mislead consumers because it does not account for real-world exposure levels.
Understanding Risk vs. Hazard: Why It Matters
There’s a big difference between hazard and risk. A hazard is any potential source of harm, while risk is the likelihood that the harm will actually happen under typical conditions. Unfortunately, Prop 65 is based on hazard, not risk. So, it focuses on the possibility of harm without considering the realistic exposure levels.
This is one of the biggest critiques scientists have about Prop 65 because without assessing real-world risk, many benign chemicals end up on the list. In short, a substance’s potential to cause harm is very different from the likelihood it will harm you at normal exposure levels.
A Real-World Example: Acrylamide in Food
One example that has stirred confusion and concern is acrylamide. Acrylamide is a natural chemical formed when starchy foods are cooked at high temperatures, like when toasting bread or frying potatoes. Animal studies show that extremely high doses of acrylamide can be harmful, but there’s no human data to support the idea that normal amounts of acrylamide in food are harmful.
The American Cancer Society and other cancer organizations confirm that there’s no need to avoid foods with acrylamide, as these foods do not increase cancer risk in humans at typical consumption levels. Nevertheless, many products containing acrylamide carry a Prop 65 warning label due to the outdated evidence from animal studies.
What to Do if You’re Concerned
If you’re concerned about a Prop 65 label, here are some steps you can take to get more clarity:
- Contact the Manufacturer – Ask them which Prop 65 chemicals are present, where in the product they’re found, and how you might be exposed to them.
- Look Up the Chemical – The California Office of Environmental Health Hazard Assessment (OEHHA) website provides information on each listed chemical.
- Consider the Evidence – Prop 65 warnings are not always rooted in evidence that applies to human health in real-life exposures. Research organizations like the American Cancer Society also provide information on common substances, offering valuable insights into true cancer risks.
Final Thoughts
While Prop 65 was initially created with good intentions, it’s caused significant confusion, particularly for those like cancer survivors who have legitimate concerns about their health. If you see a Prop 65 label, remember that it doesn’t necessarily mean the product is harmful at typical exposure levels. The label’s warning can be intimidating, but it’s worth keeping in mind that without proper consideration of exposure, these warnings don’t necessarily reflect real-world risks.
Sources:
- Acrylamide. FDA. Accessed March 5, 2024. https://www.fda.gov/food/process-contaminants-food/acrylamide-and-diet-food-storage-and-food-preparation
- Acrylamide and Cancer Risk. American Cancer Society. Revised February 11, 2019. Accessed November 18, 2024. https://www.cancer.org/cancer/risk-prevention/chemicals/acrylamide
- Proposition 65. California Office of Environmental Health Hazard Assessment. Accessed November 18, 2024. https://oehha.ca.gov/proposition-65
- IARC Monographs Hazard Classification. IARC. Published June 16, 2023. Accessed November 18, 2024. https://www.iarc.who.int/infographics/iarc-monographs-classification/
This blog is not intended as medical nutrition therapy, medical advice, or diagnosis and should in no way replace consultation or recommendation from your medical professional.
