A California law called “Proposition 65” (or “Prop 65” for short) mandates that foods, dietary supplements, and other consumer products bear warnings about cancer and birth defects if the product may cause exposures to certain substances, even at very low levels. The Prop 65 warnings are well-intentioned, but can be alarming and even misleading, since the warnings often occur on products that present no actual risk. Here's some useful information about how to interpret these warnings and how to make wise food choices.
Position 65 (“Prop 65”), or “The Safe Drinking Water and Toxic Enforcement Act of 1986,” is a California right-to-know law that was passed by voters in 19861. Among other things, the law creates a requirement for companies to inform the public about the presence – even at trace levels – of certain substances in the products they sell or use. These “Prop 65-listed chemicals” are ones for which the State of California has decided that information about the chemical’s toxicity satisfies the regulatory requirements for addition to the Prop 65 list of chemicals.
When such a substance is present or may be present in a product above a very low level, the company is required to provide “clear and reasonable” warnings to the public that the product contains or exposes the consumer to “chemicals known to the State of California to cause cancer” or “chemicals known to the State of California to cause birth defects or other reproductive harm.” Depending on the circumstances, companies may provide the warning by printing it on product labels, including it in documents that accompany the product when it is shipped to a consumer in California, or posting it on signs in California businesses2.
Prop 65 warnings are required for chemicals that are commonly present in a wide variety of everyday products such as foods, dietary supplements, cleaners, and beauty care products as well as for substances such as pesticides, gasoline, car exhaust, and cigarette smoke. As a result, warnings can be seen not only on product labels but also posted throughout California in establishments such as restaurants, coffee shops, hotels, stores, buildings, and parking garages. In addition, for certain types of food, the purveyor is allowed to provide a general Prop 65 warning on a sign posted in the establishment rather than providing a warning for each specific food that contains Prop 65 chemicals above the trigger level. These include:
Bulk fish and seafood
Bulk fruits and vegetables
Food sold in a restaurant
Alcoholic beverages sold in a restaurant or bar
Prop 65 is enforced through lawsuits brought by the State Attorney General, district or city attorneys, or private plaintiffs3. A plaintiff does not need to show that anyone has been hurt in order to bring a lawsuit.
When a Prop 65 warning occurs on a product, it needs to be considered in context with a consumer’s other environmental and dietary exposures to chemicals. You may want to contact the manufacturer and determine the substance that is the subject of the warning. You should also consider other sources of the substance in your diet and environment. Keep in mind that many foods – including fruits and vegetables with important nutrition benefits – contain trace levels of contaminants.
Lead and heavy metals are often the cause of Prop 65 warnings. If you are pregnant, breastfeeding, or planning to have children (even if you are male), you should take care to minimize your exposure to lead and other heavy metals. Consumers should also consider that some products that may contain Prop 65 listed chemicals are not required to display a Prop 65 warning – products such as pharmaceuticals, foods that contain naturally-occurring chemicals, and drinking water, as well as some products manufactured and distributed by small businesses.
Prop 65 is not a product safety law. Rather, it is a right-to-know law requiring the public to be informed when a Prop 65 listed chemical is present above a very low threshold. As the Office of Environmental Health Hazard Assessment (OEHHA), the California agency responsible for implementing Prop 65 has noted, “A Proposition 65 warning does not necessarily mean that a product is in violation of any product-safety standards or requirements4.”
The law specifically requires that the level of a listed substance triggering a Prop 65 warning is significantly lower than the level at which any harm has been documented. In many cases, the substances in question occur at levels much too low to cause any measurable health effect and no known link between exposure to the substances at these low levels and any actual risk of cancer or reproductive harm has been established.
For example, in the case of listed reproductive toxicants, the warning threshold is 1000 times lower than the level found to cause no reproductive harm5. In other words, if animal studies predict that a human could eat up to 1000 grams per day of a substance without any reproductive effect, Prop 65 would be a require a warning on a food that contains 1 gram or more of the substance in a daily serving. This is further illustrated in the figure below.
People often equate the word “chemical” with synthetic hazardous substances. However, scientifically the word simply refers to any substance that has a defined molecular structure or which can be analyzed using chemistry. In this sense, every substance on the planet and all living organisms are made of chemicals. The Prop 65 list of chemicals includes both natural and synthetic substances, and both isolated chemicals and complex mixtures; under the Prop 65 regulations these are all lumped together using the term “chemical.”
The phrase “known to the State of California” refers to the particular way that California law identifies chemicals for listing under Prop 65. A listing under Prop 65 means that the California State government has determined that the chemical meets the Prop 65-specific regulatory criteria for listing the chemical as a reproductive toxicant or carcinogen under the law6. The listing under Prop 65 does not necessarily mean that a scientific consensus has concluded that the chemical in question causes reproductive toxicity or cancer in humans.
6 California Health and Safety Code, Chapter 6.6, section 25249.8
The Prop 65 list7 includes a wide range of substances, including both man-made chemicals and those which occur in nature. The substance does not have to be intentionally added to the product to trigger the Prop 65 warning. 7 OEHHA “Chemicals Known to the State to Cause Cancer or Reproductive Toxicity” http://www.oehha.ca.gov/prop65/prop65_list/Newlist.html
Substances are typically identified for inclusion in the Prop 65 list on the basis of animal studies, although in some cases human data (such as from epidemiological studies) are also available. The validity of extrapolating data from one type of animal to another species such as humans is uncertain, due to important physiological and metabolic differences between species8; some chemicals are known to cause cancer or reproductive harm in one species but not in others, the same way that chocolate is toxic to dogs but not to humans. However, for purposes of Prop 65 the State of California often accepts data that indicate harm, or even just possible harm, in animals as sufficient to meet the regulatory requirement for Prop 65 listing.
Furthermore, Prop 65 usually does not take into account the mixture in which a Prop 65-listed chemical occurs. The physiologic effect of a chemical depends on the form in which it is ingested; studies performed using isolated or highly concentrated chemicals can give different results than those on the same chemical in a natural mixture. For example, although acrylamides are known to cause cancer in laboratory animals and acrylamides are known to occur in coffee, human epidemiological studies have shown not only that coffee does not increase the risk of cancer in humans, it can in fact reduce the risk of certain cancers9. Nevertheless, acrylamides in coffee are not exempt from the Prop 65 warning requirement because the State of California generally accepts data that show harm from an isolated chemical or in one mixture as sufficient to meet the regulatory requirement for Prop 65 listing. Californians therefore see Prop 65 warning signs in coffee shops all over the state. 8 Several references discuss this topic – see Olson et al. (2000), Shanks, Greek and Greek (2009), or Johnson (2012) as examples. 9Yu X., Bao Z., Zou J., Dong J. (2011)
A product does not have to contain a level of the substance that represents an actual risk to trigger a Prop 65 warning.
In the case of chemicals that may cause reproductive harm, the trigger is set at a level 1000 times below the level at which no measurable reproductive effect can be scientifically detected10. In other words, the Prop 65 warning would be required on a food containing a daily serving of 1 ounce or more of the chemical if animal studies predict that a human would have no reproductive effect when eating up to 62.5 pounds per day of the chemical.
In the case of chemicals that may cause cancer, the trigger is set at a level which may cause no more than 1 case of cancer in 100,000 persons exposed to the chemical at that level on a daily basis for a 70-year lifetime10.
For many Prop 65-listed chemicals, the responsibility for determining these trigger levels is placed on the companies selling products in California. In such situations, to protect themselves from lawsuits companies may decide to provide the Prop 65 warning no matter how low the level of the substance is in their product.
Thus, because of Prop 65’s stringent warning thresholds, a warning may be required under Prop 65 even if no one would ever be harmed and a warning may appear on products even when not required. 10 California Health and Safety Code, Chapter 6.6, section 25249.10(c)
Prop 65 exempts “any entity in its operation of a public water system11,” which effectively exempts public water systems from the Prop 65 warning requirements. The regulations also consider that non-exempt businesses otherwise responsible for exposure to a Prop 65-listed chemical contained in drinking water (including drinking water in foods and other consumer products) do not cause exposures when the source of the drinking water is a public drinking water supply, a commercial supplier of drinking water, or any other source of drinking water that is in compliance with all applicable primary drinking water standards so long as the chemical in question is the result of treatment of the water to achieve compliance with primary drinking water standards (e.g., chlorination by-products)12.
City, county, district, state and federal government agencies are also exempt from the Prop 65 warning requirements11.
Prop 65 warnings are not required when a company sells a product that is subject to federal labeling laws that conflict with or preempt the requirements of the California law13. This exemption applies to pharmaceutical companies, for example, since labeling of prescription drugs must be approved by the U.S. Food and Drug Administration (FDA) under federal pharmaceutical regulations14. This means a drug that contains a Prop 65 listed chemical does not provide the warning required for other products unless the warning is also required by FDA.
Prop 65 is intended to exempt small businesses having fewer than 10 employees11. However, in practice many small businesses that make consumer products are affected by the law because they sell through large distributors and retail chains. These larger parties are subject to Prop 65 warning requirements, and normally require the product manufacturer to indemnify them against any Prop 65-related expenses. Thus, the burden of Prop 65 compliance is often pushed onto small businesses despite the intent of the law to exempt them. 11 California Health and Safety Code, Chapter 6.6, section 25249.11(b) 12 Title 27, California Code of Regulations, Article 5, §25502 13 California Health and Safety Code, Chapter 6.6, section 25249.10(a) 14 Dowhal v. Smithkline Beecham Consumer Healthcare, 32 Cal.4th 910, 12 Cal Rptr.3d 262 (2004)
Many Prop 65-listed chemicals, both man-made and natural, occur widely in the environment and are therefore found in food and dietary supplements. In addition, some Prop 65-listed chemicals are naturally present in plants and animals that are used as food, such as safrole in basil and black pepper. Others are formed when food is cooked or processed, such as acrylamide in coffee or ethanol in alcoholic beverages. In a few cases, Prop-65 listed chemicals may be intentionally added to food, such as Vitamin A in vitamin supplements or fortified foods.
Prop 65-listed chemicals that commonly occur in food and dietary supplements are heavy metals such as arsenic, cadmium, lead, and mercury. These metals are widespread in soil and water, and can therefore accumulate in plants and animals. As a result, these metals find their way into foods and dietary supplements, although typically only at low levels.
With respect to lead, the Canadian government indicates that since 2004, the most significant dietary sources are beverages (including beer, wine, coffee, tea, and sodas), cereal-based foods, and vegetables15. The U.S. Food and Drug Administration provides information about the content of lead and other contaminants in various foods in its Total Diet Study database16. The chart below presents information about the average lead levels in various foods from FDA's Total Diet Survey during 2005-201116 as compared to the Prop 65 trigger level for reproductive harm.
Food grown near roads or old buildings may be contaminated with lead due to historical use of leaded gasoline and lead-based paint18, 19. Food grown near, downstream, or downwind from industrial sites, landfills, and military bases may also be contaminated with various chemicals; for example, much of the U.S. mid-west is contaminated with traces of radioactive fallout from the nuclear tests in Nevada in the 1950’s20, 21. Food from the ocean, lakes, and rivers often contains trace levels of various contaminants, such as mercury and pesticides in fish22.
Since everyone consumes water each day in one form or another, drinking water can be a source of daily exposure to Prop-65 listed chemicals. Lead, arsenic, pesticides, radioactive isotopes, chlorination by-products, and other chemicals may be found at low levels in many water supplies23.
Drinking water is potentially a much more significant source of lead in the diet than a food product that contains lead above the trigger level for the Prop 65 warning.
When a food product or any other consumer product made with drinking water contains a Prop 65-listed chemical, any portion of the chemical contributed to the product by drinking water is not used to determine whether a Prop 65 warning is needed26. 18 Mielke HW, Anderson JC, Berry KJ, Mielke PW, Chaney RL, Leech M. Lead concentrations in inner-city soils as a factor in the child lead problem. Am J Public Health 1983;73(12):1366 –1369. 19 LaBelle SJ, Lindahl PC, Hinchman RR, Ruskamp J, McHugh K. Pilot study of the relationship of regional road traffic to surface–soil lead levels in Illinois. Argonne National Laboratory, Energy and Environmental Systems Division, Center for Transportation Research, Publication ANLyES-154, 1987. 20 Radioactive Fallout from Nuclear Testing at Nevada Test Site 1950 – 1960, Hearing before a Subcommittee of the Committee on Appropriations, United States Senate. http://www.gpo.gov/fdsys/pkg/CHRG-105shrg44045/html/CHRG-105shrg44045.htm (accessed October 16, 2015) 21 Centers for Disease Control and Prevention (CDC), Radioactive Fallout from Global Weapons Testing. http://www.cdc.gov/nceh/radiation/fallout/RF-GWT_home.htm (accessed October 15, 2015) 22 Environmental Protection Agency (EPA), Studies of Fish Contamination http://www2.epa.gov/fish-tech/studies-fish-contamination (accessed October 27, 2015) 23 Environmental Protection Agency (EPA), Drinking Water contaminants http://water.epa.gov/drink/contaminants/ (accessed October 27, 2015) 24 21 CFR 165.110 Requirements for Specific Standardized Beverages – Bottled Water 25 Levin R, Schock MR, Marcus AH. Exposure to lead in U.S. drinking water. In: Proceedings of the 23rd Annual Conference on Trace Substances in Environmental Health. Cincinnati, OH, US Environmental Protection Agency, 1989. 26 Title 27, California Code of Regulations, Article 5, §25502
The Prop 65 regulations include a provision stating that Prop 65-listed chemicals that are naturally-occurring substances in food, or in other consumer products made from the food containing the substance (such as cosmetics) do not trigger the warning requirement27. Two types of “chemicals” can meet the naturally occurring definition: (1) a natural constituent of a food and (2) absorbed or accumulated chemicals that are naturally present in the environment, which are considered chemical contaminants. One example of a natural constituent of food is safrole, which is present in basil, black pepper, and other food plants. For absorbed or accumulated chemicals, examples are the heavy metals that may be present in fruits and vegetables.
This “naturally-occurring” exemption for chemical contaminants only applies to the extent that the presence of the chemical did not result from any past or present human activities and those which are outside the food company's control. Past human activities such as the use of pesticides and leaded gasoline often contribute to the presence of Prop 65-listed chemicals in the environment and hence in the food, which means the chemical is not “naturally occurring” as defined in the regulations. 27 Title 27, California Code of Regulations, Article 5, §25501
The presence of a Prop 65 warning on a food or supplement does not necessarily mean the food is less safe or pure than other comparable products.
A variety of reasons may explain the presence of a warning on one product and not on another. Some companies’ products may not contain any Prop 65 listed chemicals, or may contain low enough levels that a warning is not required. Other companies have settled a Prop 65 lawsuit by agreeing to provide the warning rather than trying to prove that the warning is not needed. In addition, some companies choose to voluntarily provide the warnings to avoid a Prop 65 lawsuit, even if their products arguably do not require warnings. Other companies are exempted from providing warnings because they have fewer than ten employees.
Thus, the presence of a warning does not necessarily mean that a product causes more exposure to Prop 65-listed chemicals than a similar product without a warning sitting on the shelf next to it. No definite correlation between the presence or absence of a Prop 65 warning and the level of Prop 65-listed chemicals in the food or supplement can be assumed.
Modern supply chains typically distribute products throughout the U.S. or a region of the U.S. It can be very difficult for companies whose products are distributed both inside and outside of California to arrange for the warning to be delivered only to customers in California. Many companies include the warning on their product label itself, in other widely-distributed literature or on their website, in which case the warning may appear no matter where the actual sale occurs.
A great deal of information is available from authoritative sources regarding chemicals in food. Here are a few sources to consider.
State of California’s Office of Environmental Health Hazard Assessment (OEHHA) website:www.oehha.ca.gov/