Proposition 65, officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, is a California law mandating that businesses inform consumers before knowingly exposing them to chemicals known to cause cancer, birth defects, or reproductive harm.

The law is designed to help California residents make informed decisions about their exposures to these chemicals. It is also one of the strictest consumer protection laws in the U.S. Businesses that fail to comply may face enforcement actions or lawsuits, with financial penalties of up to $2,500 per day, per violation.

The California Office of Environmental Health Hazard Assessment (OEHHA) maintains a list of chemicals known to the state to cause cancer, birth defects, or other reproductive harm. This list is updated regularly and includes a wide range of substances, such as pesticides, heavy metals, solvents, and ingredients found in certain products, including dietary supplements. You can find the full list here.

Businesses are required to provide a "clear and reasonable" warning before knowingly and intentionally exposing anyone to a listed chemical, unless the business can show that the anticipated exposure level will not pose a significant risk of cancer or is significantly below levels observed to cause birth defects or other reproductive harm.

These warnings can be:

For more information, visit this page.

When the warning message is provided on a dietary supplement label, it must be set off from other surrounding information, enclosed in a box. In addition, a warning symbol is required, which consists of a black exclamation point in a yellow equilateral triangle with a bold, black outline (⚠️). The symbol must be placed to the left of the text of the warning in a size no smaller than the height of the word “WARNING”. The warning symbol can be downloaded here.

Furthermore, it must comply with further content requirements specified below, which includes 4 scenarios when different wording of the disclaimer is be required, depending on the chemical - either it causes cancer, reproductive harm, or both:

When space on a dietary supplement label is limited, a short form Proposition 65 warning may be used instead of the long form. This version is more concise but must still be accompanied by the warning symbol, which consists of a black exclamation point in a yellow equilateral triangle with a bold, black outline (⚠️). The symbol must be placed to the left of the text of the warning in a size no smaller than the height of the word “WARNING” (or “CA WARNING” or “CALIFORNIA WARNING,” as permitted). The warning symbol can be downloaded here.

The short form warning must meet specific content requirements, which have changed starting January 1, 2025:

“⚠️ WARNING: Cancer – www.P65Warnings.ca.gov/food”

“⚠️ WARNING: Reproductive Harm – www.P65Warnings.ca.gov/food”

“⚠️ WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov/food”

For exposure to a listed carcinogen: “⚠️ WARNING: Cancer risk from exposure to [name of chemical]. See www.P65Warnings.ca.gov/food.”

For exposure to a listed reproductive toxicant: “⚠️ WARNING: Risk of reproductive harm from exposure to [name of chemical]. See www.P65Warnings.ca.gov/food.”

For exposure to both listed carcinogens and reproductive toxicants: “⚠️ WARNING: Cancer risk from exposure to [name of carcinogen] and reproductive harm from exposure to [name of reproductive toxicant]. See www.P65Warnings.ca.gov/food.”

For exposure to a chemical causing both cancer and reproductive harm: “⚠️ WARNING: Cancer and reproductive harm from exposure to [name of chemical]. See www.P65Warnings.ca.gov/food.”

If the product is sold online or through a Catalog, the warning may be provided in the online description or catalog instead of on the physical product label.

However, the warning must be clearly associated with the product before the purchase is completed. For online sales, this means the warning should be displayed on the product page or at checkout, ensuring the consumer sees it before finalizing their purchase.

As a brand or seller of products in California, you are responsible for determining whether Proposition 65 warnings are legally required. Here are your potential compliance strategies:

If a COA includes testing for Proposition 65-listed chemicals and indicates levels are non-detectable or below safe-harbor thresholds, you may omit a warning.

Important: verify that the COA testing scope covers relevant chemicals for your product type.

You can send product samples to third-party labs for Proposition 65 chemical analysis. If any chemical exceeds the “No Significant Risk Level” (NSRL) or “Maximum Allowable Dose Level” (MADL), you must provide a compliant warning.

To be cautious or streamline compliance, you can place the proper Proposition 65 warnings on every product you’re selling, regardless of testing. Ensure phrasing matches endpoints (cancer, reproductive, or both), includes a chemical name (e.g., “lead” or “arsenic”), the ⚠️ symbol, and a web URL. Warning must be on the product label or in online/catalog descriptions before purchase and exposure.

Failing to provide required Proposition 65 warnings can result in enforcement actions or lawsuits. Penalties can reach $2,500 per day, per violation, and cases are often pursued by private enforcers (“bounty hunters”) as well as state authorities. This makes Proposition 65 one of the strictest consumer protection laws in the U.S.

For more information, please visit the Proposition 65 website here, or consult with a legal professional.

It is up to the Brand Holder to ensure the compliance with the latest regulations, depending on the region where the products are sold.