Thorne® | California’s Proposition 65

What is California’s Proposition 65?

California’s Safe Drinking Water and Toxic Enforcement Act of 1986, now universally known as Proposition 65, is a law that applies only in the State of California. Proposition 65 mandates the publication of a list of chemicals that the State of California determines causes cancer or birth defects, and requires companies that sell products that contain those chemicals to inform California residents about the risk of exposure to such chemicals by including a warning notice on the product label.

Since 1986, the two Proposition 65 lists have expanded to include more than 800 chemicals. Even if a chemical has not been shown to cause cancer or birth defects in humans, but has been shown to do so in animal testing, the chemical is still required to be placed on the applicable Proposition 65 list.

Proposition 65 warning notices can be seen throughout California, in various settings such as restaurants, grocery stores, hotels, bars, schools, hospitals, and theme parks.

What Chemicals Are on the Proposition 65 Lists?

The two Proposition 65 lists encompass a wide range of naturally-occurring and man-made chemicals. Listed chemicals not only include ingredients found in pesticides, insecticides, and construction materials, but also ingredients contained in common household products like foods, drugs, alcoholic beverages, and nutritional supplements.

Some chemicals on the Proposition 65 list – such as lead, cadmium, and arsenic – are found naturally in the environment all over the world. Therefore, some products that naturally contain these substances can be required to carry a Proposition 65 warning notice on their product label, such as mineral and botanical ingredients contained in nutritional supplements.

Are Other States Affected by Proposition 65?

Proposition 65 only applies in California. A company that sells consumer goods in California – whether or not the company is located in California – is subject to Proposition 65's warning notice requirement. Proposition 65 warning notices are not required to be included on the labels of products that are sold in other states.

Are Products with a Proposition 65 Warning Notice Unsafe?

When a manufacturer includes a Proposition 65 warning notice on a product, it does not mean the product is unsafe. Rather, the warning notice is intended to inform California consumers of the presence of a Proposition 65-listed chemical so the consumer can make an informed decision when purchasing the product.

How Does Proposition 65 Determine the Threshold Levels for Which a Warning Notice Is Required?

Proposition 65 establishes two criteria to define the level of exposure risk. The first criterion is cancer risk, and the second criterion is birth defect or other reproductive harm risk.

The maximum daily exposure threshold for a cancer-risk chemical is determined using the "no significant risk level." The "no significant risk level" is defined as the maximum daily level of exposure that would result in not more than one additional case of cancer in 100,000 individuals exposed to that specific chemical every day for 70 years. In other words, a person who was exposed for 70 years to the maximum daily limit of the chemical at the "no significant risk level" would have no more than a one-in-100,000 chance of developing cancer as a result of that 70-year exposure.

The maximum daily exposure threshold for a birth defect-risk chemical is determined using the "no observable effect level." The "no observable effect level" is defined as the maximum daily level of exposure that has been shown to not cause any birth defects or reproductive harm in laboratory animals or humans. In addition, as a margin of safety, the "no observable effect level" is divided by 1,000 to establish the threshold for requiring a Proposition 65 warning notice for that chemical.

What is Thorne doing regarding Proposition 65?

Thorne methodically tests every raw ingredient and every finished good for identity and purity. Every incoming raw ingredient is quarantined in our facility until it is tested and its identity and purity is verified. As part of our purity testing, raw materials are tested for the suspected presence of chemicals listed by California’s Proposition 65. If a Thorne product contains a naturally-occurring chemical in an amount that is above a Proposition 65 threshold, then we will place the appropriate warning notice on the product label. However, in every case, the amount of lead or other chemical in a Thorne product that requires a Proposition 65 warning notice will be within the U.S. Pharmacopeia guideline considered safe for daily intake. You can read more about Thorne’s quality standards here.