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Last modified: June 26, 2024

California’s proposition 65

Overview: California’s proposition 65

Proposition 65 requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects, or other reproductive harm.

Some suppliers manufacture specific versions for sale only in California with reduced levels of Prop 65 listed substances below notice requirements. If you provide a ship-to address within California, you’ll automatically receive California-formulated versions of these products.

The State of California believes that the public has a right to know about products that contain naturally occurring or introduced toxic compounds. The following warning is placed on these products:



Products that aren’t found to contain toxic compounds listed in Prop 65 don’t require this label.

Product safety & prop 65

A Prop 65 warning doesn’t mean that the use of an individual product will cause cancer or reproductive harm when used as directed. There’s a lot of debate over what a toxic level or a cumulative toxic level is for each chemical.

Good quality suppliers take every precaution possible to ensure their products are safe. At Emerson, we’re confident that the suppliers we carry care deeply about delivering products that are not only safe but beneficial to patient health. If you see the Prop 65 warning on a product, it demonstrates that the company is compliant with the law.

For example, for listed reproductive toxins, the stated level requiring a warning label is 1,000 times lower than the lowest level at which animal studies reported no reproductive health effect. At this dose, the risk of harm may be very low, yet products would still require Prop 65 warnings.

Another example is lead. The Prop 65 notice limit for lead is 0.5 mcg per day. The U.S. Environmental Protection Agency’s safe limit for lead in drinking water is 15 mcg/L per day. To help with perspective on how some of the standards set by Prop 65 are extremely low and how many foods contain naturally occurring lead from the soil they were grown in, 1 oz. of dark chocolate can contain about 0.6 mcg of lead, which would exceed the safe limit of lead by Prop 65 standards.

Site warnings & messaging

Californian online shoppers are shown Prop 65 warning statements prior to purchasing products. If you provide a ship-to address within California, and you are purchasing a product with a Prop 65 warning statement on the label, you will also receive a Prop 65 warning statement for that product on your Review Order page.

Platform prop 65 warning.
The Prop 65 warning on the Emerson site.


Which types of substances exist in dietary supplements that fall under prop 65?

Prop 65 regulates chemicals officially listed by California as having a 1 in 100,000 chance of causing cancer over a 70-year period or 1,000 times below the lowest level at which measurable reproductive harm may be detected in two ways:

  1. The first statutory requirement of Prop 65 prohibits businesses from knowingly discharging listed chemicals into drinking water sources or onto land where the substances can pass into drinking water sources.
  2. The second prohibits businesses from knowingly exposing individuals to listed chemicals without providing a clear and reasonable warning.

The list contains a wide range of naturally occurring and synthetic substances that are known by the State of California to cause cancer, birth defects, or other reproductive harm when certain exposure thresholds are met. These chemicals include additives or ingredients in pesticides, common household products, food, drugs, dyes, or solvents. Listed chemicals may also be used in manufacturing and construction, or they may be byproducts of chemical processes, such as motor vehicle exhaust or roasting coffee beans.


Californians aren’t strangers to these warnings, given they’re routinely posted in hotels, gas stations, coffee shops, etc., and are found on many products they encounter on a daily basis.

Which types of prop 65 listed chemicals exist in dietary supplements?

One example of a nutrient possibly requiring labeling if above a certain dosage is vitamin A (retinol/retinyl esters). Additionally, many plant-based foods, even when grown organically, can contain lead, mercury, or other heavy metals due to the absorption of low amounts that naturally occur in soil.

Should I be concerned?

We should all be concerned about our cumulative exposure to toxic chemicals in our environment and their impact on our health. Prop 65 endeavors to make Californian consumers aware of potential exposures so that they may make informed choices that have the potential to affect their health.

As a healthcare provider, am I responsible for informing patients of exposure to harmful chemicals?

California businesses with 10 or more employees are responsible for informing consumers of potential exposure to chemicals on the Prop 65 list. 


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