Lead and Cadmium in Food FAQs

Why should we worry about lead and cadmium?
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The California Office of Environmental Health and Human Hazard Administration (OEHHA) has listed cadmium and lead as chemicals known to cause birth defects or other reproductive harm.1

Lead has been widely recognized as the single most significant environmental health threat to children.2 Lead exposure has been a significant public health issue for decades and is associated with neurological impairment, such as learning disabilities and lower IQ, even when ingested at low levels.3, 4, 5 “No amount of lead ingestion is ‘safe’ for children,” asserts Sean Palfrey, MD, a practicing pediatrician and professor of Pediatrics and Public Health at Boston University School of Medicine. “Pregnant women and young children with developing brains in particular should avoid any ingestion of lead.”

Chronic exposure to cadmium  can cause kidney, liver, and bone damage in humans, and children are more susceptible to the effects of exposure to low doses of cadmium over time. Cadmium may also cause developmental problems, such as decreased birth weight, harm to neurobehavioral development, and male reproductive toxicity, all of which have been observed in animal studies.6, 7

Lead and cadmium accumulate in the body over time, increasing the total body burden of these heavy metals over decades. Ingesting even small amounts of these metals will add to existing body burdens and should be avoided.3, 4, 5, 6, 7

What are the sources of lead and cadmium?
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Cadmium and lead are toxic heavy metals that are released into the environment through manmade industrial processes including mining, burning fossil fuels such as coal or oil, incineration of municipal waste (plastics/batteries), and manufacturing and smelting, the largest source of airborne cadmium. Cadmium and lead also enter soil through the disposal of sewage sludge, or the application of pesticides or phosphate fertilizers (which can contain high levels of cadmium).4, 7

Once released into the atmosphere, respirable-sized airborne particles attach to dust, can travel long distances, and will be deposited onto the earth, where they move easily through soil layers and can be taken up into the food chain. Once mined and introduced into the atmosphere, these heavy metals can move from air to soil to water, but do not break down easily and will remain for decades.4, 7

How are we exposed to lead and cadmium?
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The main route of human lead and cadmium exposure occurs via ingestion from food as well as through contaminated water and soil.4, 7 Lead and cadmium in food are ubiquitous and do not seem to discriminate between natural, certified organic, and non-organic products. One or both of these metals have been found in various foods including baby foods (made with carrots, peaches, pears, sweet potatoes), dietary supplements, vitamins, protein powders, seaweed snacks, ginger cookies, packaged peaches/pears, various fruit juices, as well as chocolate.

Another way we are exposed to lead and cadmium is through inhalation from dust or pollution from industrial processes. Additionally, cadmium is present in cigarette smoke.

How do lead and cadmium get into chocolate products?
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Cadmium and lead may contaminate the chocolate product at many points through the “bean to bar” process; these sources may depend on the cacao growing, fermenting, processing, manufacturing, shipping, and packaging practices.

One significant source is manmade pollution created by industrial processes as described above. Due to the persistence of these heavy metals in soil, they remain present even after the industrial source has been removed. Another source of these heavy metals in chocolate is through direct application of pesticides (lead and cadmium), phosphate fertilizers (cadmium), as well as sewage sludge disposal (lead and cadmium).4, 7

A third source of lead and cadmium is contamination through one of the various processing steps a bean undergoes after the harvest. These steps include fermentation, drying of the cacao bean, and manufacturing processes such as grinding, refining, and conching. Other opportunities for contamination are shipping, handling, and finally, packaging. Studies have shown that much of the “lead contamination in (chocolate) products occurs after the beans are harvested and dried, during the shipping of those beans and/or the manufacturing of cocoa and chocolate products.”.8, 9

How can manufacturers prevent lead and cadmium contamination in their products?
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There may not be a single remedy to remove lead and cadmium in chocolate products. Chocolate manufacturers must understand the manufacturing practices and possible manmade sources of contamination and then take steps to identify the source(s) of the contamination. For example, the equipment used to process chocolate could be a primary source of lead or cadmium. Similarly, water used in processing, or shipping containers, may be high in lead. Once the source(s) are identified, suppliers and manufacturers can improve their practices; increase supply chain transparency; and effectively remove lead and cadmium from their final product.

Another protocol many agree on is for the cocoa bean growers to test the soil in which they grow the cocoa beans before planting the beans, and avoid the use of lead/cadmium-laden pesticides, as well as avoiding phosphate fertilizers, which often contain high levels of cadmium.

How can I tell if lead or cadmium is in the chocolate product I purchase?
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The only way to tell if lead or cadmium is in a product is to have the product tested for heavy metals by a certified lab. However, under California’s Proposition 65, manufacturers must warn consumers if a product contains chemicals above set levels known to cause cancer and/or birth defects or other reproductive harm.

Doesn’t the government protect us from chemicals like lead and cadmium in the products we buy?
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The FDA does not consistently monitor food for lead and cadmium contamination. California has the most health protective standards in the country for the presence of lead and cadmium in consumer products, and requires the manufacturer to warn consumers if a product contains chemicals known to cause cancer and/or birth defects or other reproductive harm, above the safe harbor level set by California’s Office of Environmental Health Hazard Assessment.

Will I get sick if I eat chocolate products with cadmium?
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It is difficult to predict which chemical exposure(s) will trigger an adverse health effect in a person, due to interindividual variation (depending on biological and/or genetic factors). What we do know is that lead and cadmium are toxic heavy metals and accumulate in the body where they remain for decades. The first step in preventing exposure is to identify the chemical itself and then try and avoid it. With all chemical exposures, the most vulnerable populations are developing fetuses, children, the elderly, and those most impacted from working or living near industrial and manufacturing plants.

What can I do to help make sure the chocolate products I buy are free of cadmium?
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Check the lists that we have published on our web site and buy the product that do not require a warning. You can also write to your favorite chocolate manufacturer(s) and ask them to fix this issue the check back to see our list as we hope manufactures will soon look down their supply chains and reduce the levels below California’s safe harbor level for reproductive harm and let us know so we can retest.

What is Proposition 65 and how is As You Sow enforcing it?
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California Safe Drinking Water and Toxic Enforcement Act of 1986 is a consumer-right-to-know law voted into existence in 1986 by California citizens. It protects Californians by requiring the manufacturer to warn consumers if a product contains chemicals known to cause cancer and/or birth defects or other reproductive harm. While the law is CA specific, the enforcement of the law has a positive impact on all of the consumer products available through the US. Many product manufacturers, when reformulating to reduce toxins for the California market, will then sell the same product across the US and even globally.

For over 23 years, As You Sow has been successfully enforcing the California Safe Drinking Water and Toxic Enforcement Act of 1986 and has worked with manufacturers to reformulate hundreds of products in order to provide the consumer with a cleaner, healthier product. These include mercury in fish, toluene in nail polish, lead in herbal supplements, formaldehyde in portable school classrooms, and toxic chemicals in cosmetics and laundry detergent. You can see a list of some of these products on our Toxic Enforcement page.


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  1. California Office of Environmental Health and Human Hazard (OEHHA).
  2. National Research Council, Measuring Lead Exposure in Infants, Children, and Other Sensitive Populations. Washington, D.C.: National Academy Press, 1993, p. 1. Centers for Disease Control, Preventing Lead Poisoning In Young Children, October 1991.
  3. EPA 2013 Integrated Science Assessment for Lead.
  4. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Lead. August 2007.
  5. NRDC: Our Children At Risk, The Five Worst Environmental Threats to Their Health. Chapter 3: Lead.
  6. Agency for Toxic Substances and Disease Registry (ATSDR). ToxFAQs for Cadmium. 2012.
  7. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Cadmium. September 2012.
  8. Rankin CW, Nriagu JO, Aggarwal JK, Arowolo TA, Adebayo K, Flegal AR. Lead contamination in cocoa and cocoa products: isotopic evidence of global contamination. Environ Health Perspect. 2005;113:1344–1348. [PMC free article] [PubMed]
  9. Yanus RL, Sela H, Borojovich EJ, Zakon Y, Saphier M, Nikolski A, Gutflais E, Lorber A, Karpas Z. Trace elements in cocoa solids and chocolate: an ICPMS study. Talanta. 2014 Feb;119:1-4. doi: 10.1016/j.talanta.2013.10.048. Epub 2013 Oct 28.