August 10, 2017
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  4. Lead and Dietary Supplements: Putting Prop 65 in Perspective

The future looks dim for the dietary supplement industry, its retailers and consumers in California. The Safe Drinking Water and Toxic Enforcement Act of 1986, better known by its original name of Proposition 65 (Prop 65), was passed by California voters in a referendum vote in November, 1986. At the time, well intentioned liberal voters of California sought to reign in perceived environmental contamination of all sorts by placing restrictions on allowable levels of a broad list of industrial chemicals viewed as threats to the health of humans and their environment.

This list, which must be updated at least once a year, was first published in 1987, and has grown to include over 800 chemicals believed to cause cancer, or birth defects, or other reproductive harm. As explained by the Office of Environmental Health Hazard Assessment (OEHHA), the department within California’s Environmental Protection Agency (Cal/EPA) responsible for administration of the Proposition 65 program:

“Proposition 65 requires businesses to notify Californians about significant amounts of chemicals in the products they purchase, in their homes or workplaces, or that are released into the environment. By providing this information, Proposition 65 enables Californians to make informed decisions about protecting themselves from exposure to these chemicals. Proposition 65 also prohibits California businesses from knowingly discharging significant amounts of listed chemicals into sources of drinking water.”

OEHHA is also supposed to evaluate all currently available scientific information on substances considered for placement on the Proposition 65 list. On the surface, the people’s initiative appears to put in place a beneficial protection for all residents of the state. But in the case of dietary supplements, we must ask whether the good intentions of the people’s initiative have delivered true benefits or, conversely and ironically, jeopardized their long term health status. The answer to the question must be sought through interpretation of the two words “significant amounts” in the opening line of the quote above.


The list of chemicals in Proposition 65 contains a wide range of naturally occurring and synthetic chemicals that are known to cause cancer or birth defects or other reproductive harm. These chemicals include additives or ingredients in pesticides, common household products, food, drugs, dyes, or solvents. It is the inclusion of “naturally occurring” substances on the list that has eventually presented a serious problem to the dietary supplement industry.  What are the “significant amounts” of these “naturally occurring” substances that pose a significant danger to the consumer? This is the overriding conundrum posed by Proposition 65 that requires close examination.


Analytical technology has advanced to a level of such precision that it is now possible to find traces of toxic heavy metals in virtually all foods and beverages. Of prime concern to the dietary supplement industry are lead, arsenic, cadmium and mercury. All four metals are listed in Proposition 65 and all are naturally present in foods. They cannot be avoided. They will be in foods bought at the market and consumed at home; in foods consumed at restaurants, even in vegetables you grow at home.

Just as these heavy metals are present in foods, they are consequently found in supplements made of natural materials, whether from plants or animals. And therein lies the problem for the dietary supplement industry, its retailers and consumers in California.

Responsibility and Warnings

Businesses are required to provide a “clear and reasonable” warning before knowingly and intentionally exposing anyone to a listed chemical. This warning can be given by a variety of means, and most often appears on the product label or on a store shelf sign. The primary warning reads: “WARNING: This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm.” It is referred to as the Proposition 65 safe harbor warning because, by regulation, it is deemed to be a clear and reasonable warning of the presence of chemicals in a product at levels that exceed the “No Significant Risk Levels” (NSRLs) for carcinogens and/or the “Maximum Allowable Dose Levels” (MADLs) for chemicals causing reproductive toxicity as delineated in the list of chemicals covered by Prop 65.

Indeed, there are three designated warnings. The appropriate warning is dictated by whether the chemical was added to the Proposition 65 list as a carcinogen or a reproductive toxin. The warnings are:

  1. WARNING:  This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm.
  2. WARNING:  This product contains a chemical known to the State of California to cause cancer.
  3. WARNING:  This product contains a chemical known to the State of California to cause birth defects or other reproductive harm. 

In the case of lead in dietary supplements, warning number 3 most often applies. From the California EPA list of “Chemicals Known to the State to Cause Cancer or Reproductive Toxicity” (i.e. the Prop 65 list), we find a categorization of the State’s concerns for listed forms of lead. Lead in food, food products and supplements fall under entries listed only as “Lead.”

Chemical Type of Toxicity Date Listed NSRL or MADL  (µg/day)a
Lead developmental, female, male 27-Feb-87 0.5
Lead and lead compounds cancer 1-Oct-92
Lead 15 (oral)
Lead acetate cancer 1-Jan-88 23 (oral)
Lead phosphate cancer 1-Apr-88 58 (oral)
Lead subacetate cancer 1-Oct-89 41 (oral)

For some, but not all chemicals in the Prop 65 list, the amount of the offending chemical present in the finished product can further dictate which warning is to be applied. Such is the case for lead. From the California publication entitled…

Office of Environmental Health Hazard Assessment

Proposition 65 No Significant Risk Levels (NSRLs) for Carcinogens and

Maximum Allowable Dose Levels (MADLs) for Chemicals Causing Reproductive Toxicity

We find No Significant Risk (of cancer) Level (NSRL) for naturally occurring lead to be 15 mcg per day. (See excerpt below) This means that when more than 15 mcg per dose is served up, a supplement should carry warning number 1: WARNING:  This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm.

NSRL(µg/day) MADL (µg/day)
Lead 15 (oral) 0.5
Lead acetate 23 (oral)
Lead phosphate 58 (oral)
Lead subacetate 41 (oral)

If a supplement delivers 15 mcg or less, yet more than 0.5 mcg of lead in a daily serving, warning number 3 would apply, i.e. WARNING:  This product contains a chemical known to the State of California to cause birth defects or other reproductive harm. Finally, when the amount of lead in a daily serving of a supplement is less than 0.5 mcg of lead (the safe harbor level), no warning is required.

Once a chemical is listed in Prop 65, businesses have 12 months to comply with warning requirements. Lead, mercury, arsenic and cadmium were part of the original list of substances in the Act that was passed in November, 1986. By inference then, a great number of dietary supplements sold in California and containing significant amounts of natural ingredients should have borne warning labels for heavy metal content before December 31, 1988. But that didn’t happen.

Perhaps some avoided placing the warning on labels because a warning can be side-stepped if the amount of listed chemical or chemicals in the product is low enough to pose no significant risk of cancer, or is below levels believed to cause birth defects or other reproductive harm. So what are those safe levels alleged to be? Prepare to fully engage your mind, for the explanation of safety buried within Prop65 is somewhat arcane.


For chemicals listed as causing cancer, the “no significant risk level” is defined as…

“the level of exposure that would result in not more than one excess case of cancer in 100,000 individuals exposed to the chemical over a 70-year lifetime.”

In other words, a person exposed to the chemical at the “no significant risk level” for 70 years would not have more than a “one in 100,000” increased chance of developing cancer as a result of that exposure.

The definition reflects a disquieting ignorance upon which portions of Proposition 65 are built. Genetic variation among human individuals grants each of us a greater or lesser strength of resistance to cancer causing agents. Our genetic makeup, for example, determines the abundance and vigor of specific enzymes and enzyme systems known to dismantle or detoxify potential cancer causing agents. Genetics can and does influence susceptibility to certain cancers in disregard of environmental factors. Indeed, the myriad influences of genetic/hereditary, dietary and lifestyle factors on risk of developing cancer effectively confound attempts to establish a legitimate “no significant risk level.” Yet the people of California, in their collective, relative ignorance of the science required to write meaningful legislation on the topic, voted Proposition 65 into life.

Birth Defects & Reproductive Harm

For chemicals that are listed as causing birth defects or reproductive harm, the definition of “no observable effect level” is more straightforward. It is…

“the level of exposure that has been shown to not pose any harm to humans or laboratory animals.”

In the case of reproductive harm at least, there is extensive research offering some guidance. But again, in order to establish dosage levels that would reduce the risk to everyone, even those most susceptible due to their genetic makeup, for instance, the acceptable intake level for some of the listed chemicals is impossibly low. “Impossibly” here means beyond reality; levels set lower than can be achieved if one lives in the environment of present-day California.

The true problem with Proposition 65 as it relates to dietary supplements appears in the next step of the definition of “no observable effect level.” The level or dosage below which one can expect “no observable effect” according to the scientific literature is, within Prop 65,

“divided by 1,000 in order to provide an ample margin of safety.”

Therefore, a dietary supplement can be in violation of Prop 65 if the level of a heavy metal is more than 1/1000th of the amount acknowledged by science to pose no harm. This miniature magnitude may be commendably safe, but it may also be impossible to achieve in the real world. Such an extreme limitation presents an insurmountable barrier for most supplements fashioned from natural materials. It lowers the measure of heavy metals at which violations of Prop 65 will occur to unrealistic minimums; levels that cannot reasonably be achieved. Nevertheless, businesses subject to Proposition 65 are required to provide a warning if they cause exposures to chemicals listed as causing birth defects or reproductive harm that exceed 1/1000th of the “no observable effect level.”

OEHHA has named the absurdly low safety levels “safe harbor levels.” They are the numbers that, when exceeded in a product, mandate a warning on the label of a dietary supplement. A business has “safe harbor” from Proposition 65 warning requirements if exposure to a chemical occurs at or below these levels. These safe harbor numbers, at 1/1000th of a normally safe intake, certainly guarantee no significant risk from chemicals listed in Prop 65. But they also require that many ultimately safe products carry alarming and unnecessary warnings if their content of a listed chemical or metal slips above the unrealistic safe harbor level. A dietary supplement that actually carries no true danger may have to brand itself with unqualified warnings:

For carcinogens:

“WARNING: This product contains a chemical known to the State of California to cause cancer.”

For reproductive toxins:

“WARNING: This product contains a chemical known to the State of California to cause birth defects or other reproductive harm.”

A Way Out – Under 10

Prop 65 does, however, provide two routes of escape. One avenue of escape permits businesses with less than 10 employees (and government agencies) exemption from Proposition 65’s warning requirements. This loophole, we can assume, was included in the law in recognition of the limited fiscal resources available to small companies. Defending themselves against Prop 65 litigation could presumably cripple or destroy a company of 10 or fewer employees. Apparently, a company with fewer than 10 employees is also presumed to be so small that its distribution of products into the California marketplace would be too limited to pose a grave danger even if the dietary supplements contain substances beyond safe harbor limits.

A Way Out – Naturally Occurring

Another path to exemption from Prop 65 regulation is permitted if the manufacturing company can prove that the levels of heavy metals are naturally occurring in the materials making up the product, and are not the result of addition or contamination in manufacturing, that is, not added by man or as a result of human activity. The naturally occurring exemption is sensible and rational. Unfortunately, as of this writing, it has never been successfully litigated at trial and won by any dietary supplement company defending itself against Prop 65 sanctions.

But that is a legal point of debate, and the concern of the people of California, as presented by Prop 65, is less about legality and more about toxicity. People ultimately want to know whether a dietary supplement is dangerous.

By the numbers

The primary contaminant at issue for dietary supplements is lead. This heavy metal is ubiquitous in the world environment, and its widespread presence is believed to be largely – but not entirely – due to the activity of man over past millennia. Lead is naturally occurring in rocks that make up the Earth’s crust, mostly in the form of the minerals galena (lead sulfide), anglesite (lead sulfate) and cerussite (lead carbonate), and can be spewed into the atmosphere by erupting volcanoes, eventually settling onto agricultural soils and reservoirs. Rain, that must filter down through topsoil and rock on its way to replenish aquifers can also pick up traces of lead along the way, putting lead into our drinking water. Lead is now found in all plants tested, whether plucked from the land or dredged from the sea. It is found in all animals and in all humans. It is natural and unavoidable, yet our exposure to it has been increased due to lead’s use in man-made chemical compounds that have a number of industrial applications.

The human body is not just a repository for all lead it encounters throughout a lifetime, however. We can excrete lead almost as quickly as it comes in. That is an adaptation developed over millions of years of human evolution in response to the natural presence of lead in the environment. In 30 days, the blood level of lead is cut in half.

But problems arise when more is coming in than a body can throw off. The risk is more acute when one’s body mass is small. Children are at greatest risk of brain and neurological damage (potentially irreversible). Blood lead levels as low as 10 micrograms per deciliter (100 cubic centimeters of blood) have been associated with impaired neurobehavioral development in children and infants. Those levels are also of concern in pregnant women.[1] As a result, it is fair and legitimate that lead has become a primary point of attack of those wishing to enforce Proposition 65.

But the devil is in the numbers. What amounts of lead are truly dangerous and, therefore, worthy of attack? Opinions vary among the U.S. FDA (Food and Drug Administration), WHO (the World Health Organization), and, of course, the quantities codified in Prop 65. The ability of the human digestive tract to absorb dietary lead must be considered too in any evaluation of apparent danger.

The chart below identifies a group of dietary supplements manufactured entirely from plant derived materials such as cereal grasses, powdered whole vegetables, and botanical extracts. In each case, the ingredients in the supplement were selected based in part on their verified low content of heavy metals. The chart shows 1.) The size of the recommended dose, 2.) The amount of lead delivered by that dose (i.e. exposure), and 3.) The dose’s percentage of the Prop 65 safe harbor limit of 0.5 mcg per day. Analyses of only specific production lots that exceeded Prop 65 are shown, while the names of the products are excluded to protect the innocent.

The next columns to the right show 3a.) The amount of lead in micrograms that can actually be expected to be absorbed at a common percentage of 7.5%, followed by, 4.) The relationship of that absorbed lead to the Prop 65 safe harbor limit of 0.5 mcg per day expressed as a percentage of the 0.5 mcg limit. If percentages in columns #3a and #4 exceed 100% there may be cause for concern. Those high numbers are in red.

Lead content of Prop 65 noticed products (with 7.5% absorption risk)
Product’s lead content mcg/gm Product dose in gm Gross % of P65 0.5 µ limit Absorption in mcg. @ 7.5% Absorption % of P65 0.5 µ limit Absorption % at normal safety limit of 500 µ limit
0.49 1.28 0.6272 125.44% 0.0470 9.41% 0.009%
1.07 1.28 1.3696 273.92% 0.1027 20.54% 0.021%
0.77 1.28 0.9856 197.12% 0.0739 14.78% 0.015%
0.39 12 4.68 936.00% 0.3510 70.20% 0.070%
0.78 12 9.36 1872.00% 0.7020 140.40% 0.140%
0.16 12 1.92 384.00% 0.1440 28.80% 0.029%
0.61 12 7.32 1464.00% 0.5490 109.80% 0.110%
0.49 12 5.88 1176.00% 0.4410 88.20% 0.088%
0.31 12 3.72 744.00% 0.2790 55.80% 0.056%
0.7 28.74 20.118 4023.60% 1.5089 301.77% 0.302%
0.405 31.34 12.6927 2538.54% 0.9520 190.39% 0.190%
0.162 37.57 6.08634 1217.27% 0.4565 91.30% 0.091%
0.38 37.57 14.2766 2855.32% 1.0707 214.15% 0.214%
0.36 30.17 10.8612 2172.24% 0.8146 162.92% 0.163%
0.05 15 0.75 150.00% 0.0563 11.25% 0.011%
0.068 15 1.02 204.00% 0.0765 15.30% 0.015%
0.088 15 1.32 264.00% 0.0990 19.80% 0.020%
0.047 15 0.705 141.00% 0.0529 10.58% 0.011%
0.066 15 0.99 198.00% 0.0743 14.85% 0.015%
0.064 15 0.96 192.00% 0.0720 14.40% 0.014%
0.06 15 0.9 180.00% 0.0675 13.50% 0.014%
0.09 15 1.35 270.00% 0.1013 20.25% 0.020%
0.11 15 1.65 330.00% 0.1238 24.75% 0.025%
0.1 15 1.5 300.00% 0.1125 22.50% 0.023%
0.21 15 3.15 630.00% 0.2363 47.25% 0.047%

According to the scientific literature, absorption of lead from food ranges downward from 10%. The presumption of a 7.5% common rate of absorption is legitimate based on the literature. Dietary elements may also either enhance or inhibit absorption. For example, a higher intake of vegetables would correlate to a lower absorption of lead due to the alkalinizing effect of vegetables and high fiber component of the diet. Alkalinization would retard lead solubility and absorption, and high fiber would decrease gut transit time, further limiting the opportunity for absorption.

There is some irony to be found here. On the one hand, plant based foods drive up lead content of dietary supplements when used therein as evidenced in the chart above, but it is precisely plants’ content of vitamin C, calcium, iron, zinc and phosphorus (among other nutrients) that help block lead absorption. Vitamin C, folic acid (vitamin B9), thiamin (vitamin B1) and pyridoxine (vitamin B6) additionally hasten the excretion of lead, and are abundant in fresh vegetables.

Reality Check

If we recall that the 0.5 mcg per day “safe harbor level” of Prop 65 is 1,000 times lower than the scientifically established “no observable effect level,” then it might be useful to re-evaluate the frightening percentages in columns #3a and #4 above against a fictitious Prop 65 value that is 1000 times greater than 0.5 mcg, or 500 mcg. When that exercise is carried out in column #5 above (the blue numbers), we find that most of the previously offending dietary supplements would actually deliver less than one-tenth of a percent of the normal amount of lead considered to contribute no observable biological effect. The worst offender on the list only rises to three-tenths of one percent.

If a safe exposure level of 500 mcg per day nevertheless seems fearfully high, that fear is tempered by data showing adult daily ingestion of lead to be around 90 mcg per day for a 200 pound adult in the U.S., and by FDA research data that identifies 750 mcg per day as the minimal exposure level that may pose a threat to adult health. More on that follows

Returning our attention to the amount of lead that can be added to our total exposure by dietary supplements, we see that amounts contributed by them compare favorably against lead levels found in fresh food. The schedule below, for servings of 4 ounces each, was compiled by Michael Mooney from lead analyses of the U.S. food supply published by the FDA.

Food Lead in 4 oz (mcg)
Shrimp, boiled 23.80
Italian salad dressing 12.20
Mixed nuts, no peanuts, roasted 10.20
Liver, beef, fried 9.00
Brussels sprouts, fresh, boiled 7.90
Sweet potato, fresh, baked 7.20
Spinach, boiled 7.00
Dry table wine 6.80
Avocado, raw 4.50
Honey 4.50
Watermelon, raw 4.50
Raisin bran cereal 4.10
Raisins, dried 3.50
Cottage cheese 4% milk fat 3.40
Cucumber, Raw 3.40
Peach, raw 3.40
Granola cereal 3.00
Shredded wheat cereal 3.00
Whole wheat bread 2.80
Onions, mature, raw 2.70
Apple, red, raw 2.60
Green peas, boiled 2.20
Lima beans, boiled 2.20
Strawberries, raw 2.00
Eggs, boiled 1.50
Whole milk 1.20
Courtesy Michael Mooney

WHO’’s latest comprehensive report on food contaminants reminds us that…

“Food categories with the highest frequency of detectable lead include meat, especially offal, organ meats and wild game, shellfish (particularly bivalves), cocoa, tea, cereal grains and products, and vegetables.”[2]

So let’s make a meal of it. Let’s pretend you have just eaten a meal of shrimp scampi, 4 oz. worth, with Brussels sprouts and green peas as your vegetable (2 ounces each) accompanied by a light salad of spinach, avocado, cucumber, a sliced, hardboiled egg and a little Italian dressing. You chose a healthful dessert of watermelon pieces and sliced strawberries, 2 oz. each. But your major indulgence was a relaxing 4 oz. glass of dry wine with the meal. Your total lead intake from this one dinner would be 49.3 mcg. Keep in mind that food, nutrients and toxic lead passing through the gastrointestinal tract are still outside the body. In the above scenario, our 49.3 mcg of lead represents exposure only until absorption actually takes place.

For us in the United States, how does food affect our dietary intake of lead if we look beyond our fanciful meal? Extensive analyses outlined in the WHO report allow the compilation of the following charts that help illustrate the current state of our dietary intake of lead; our dietary exposure. The figures are based on a person’s body weight, with a commonly expected intake of 0.03 mcg of lead per kilogram of body weight among children and adults in the U.S.[3] It is apparent from these figures that the population at large does not persistently indulge in meals as rich as the one outlined above, for the calculated total daily exposure for lead do not approach our one sumptuous meal.

U.S. Common Lead Exposure
Weight in Lbs. Weight in kg. Total daily Pb exposure at 0.03µ/kg (mcg) % of P65 0.5 µ limit
40 18.14396 0.54 1088.64%
50 22.67995 0.68 1360.80%
60 27.21594 0.82 1632.96%
70 31.75194 0.95 1905.12%
80 36.28793 1.09 2177.28%
90 40.82392 1.22 2449.44%
100 45.35991 1.36 2721.59%
110 49.8959 1.50 2993.75%
120 54.43189 1.63 3265.91%
130 58.96788 1.77 3538.07%
140 63.50387 1.91 3810.23%
150 68.03986 2.04 4082.39%
160 72.57585 2.18 4354.55%
170 77.11184 2.31 4626.71%
180 81.64783 2.45 4898.87%
190 86.18383 2.59 5171.03%
200 90.71982 2.72 5443.19%

As you can see, merely eating normally puts one in gross violation of Propositions 65’s safe harbor limit for lead (the red numbers.)

Infants and children, whose appetites are fueled by rapid growth, customarily take in 2 to 3 times the amount of food taken in by an adult per kilogram of body weight. As a result, their exposure to lead per kilogram is greater, 0.13 mcg/kg for infants and 0.11 mcg/kg for toddlers. A chart compiled from statistics submitted to WHO by U.S. researchers provides the data below:[4]

U.S. National Lead Dietary Exposure – small children
Infants birth to 18 months
Weight in Lbs. Weight in kg. Total daily Pb exposure at 0.13µ/kg (in mcg) % of P65 0.5 µ limit
5 2.267995 0.29 589.68%
6 2.721594 0.35 707.61%
7 3.175194 0.41 825.55%
8 3.628793 0.47 943.49%
9 4.082392 0.53 1061.42%
10 4.535991 0.59 1179.36%
Children to 2 years old
Weight in Lbs. Weight in kg. Total daily Pb exposure at 0.13µ/kg (in mcg) % of P65 0.5 µ limit
26 11.79358 1.30 2594.59%
28 12.70077 1.40 2794.17%
30 13.60797 1.50 2993.75%
32 14.51517 1.60 3193.34%
34 15.42237 1.70 3392.92%
36 16.32957 1.80 3592.50%

Exposure for above populations appears greater because per capita consumption of food is greater per kg of body weight.

Again we see that normal food consumption fails to satisfy Prop 65 guidelines.

Do we need to worry? Not really. Lead levels in foods have declined over time in many developed countries. Elimination of lead additives from most gasoline in the 1970s and from paints is credited with much of the reduction in exposure. The cutback in industrial use has dramatically benefitted the food supply. From 1980 to 2006, lead levels in food dropped 75% in New Zealand, 95% in the United Kingdom, and 50% in France and Canada. In the U.S., lead intake by teenage males declined from 70 mcg per day in 1976 to 3.45 mcg in 2000, another 95% drop.[5]These are nationwide statistics that were, of course, totally uninfluenced by Prop 65.

Are these declines in lead exposure enough to save us? Let’s look to statistics on the segment of the population most vulnerable to damage from lead exposure, small children, in order to help assess our risk. Data compiled from around the world by WHO has identified a possible decrease of one-half IQ point if daily dietary exposure of the infant or small child reaches 0.8 mcg per kilogram of body weight. That figure is 6.15 times greater than the 0.13 mcg/kg statistic for children in the U.S. It would appear that our most vulnerable segment of the U.S population, the group that eats 2 to 3 times more food per kilogram of body weight when compared to adults, is still not at risk of lead poisoning, having, in general, just one sixth the exposure that might minimally affect brain development.  (It should be noted that this is a discussion of generalities, and children raised in certain mining towns or near heavy industry may be at greater risk.)

Mathematical analyses seem to imply that Prop 65 safe harbor levels for lead are unduly alarmist in nature. Are the limits established within Prop 65 reflective of an emotional and misguided attempt by an inflamed public to protect themselves from irrationally perceived dangers? Perhaps. It requires a nuanced and well informed understanding of the science surrounding each chemical contaminant itemized in Proposition 65 in order to assess whether or not the safe harbor level established for a contaminant is appropriate. Some of the safe harbor levels established by the Act may very well be accurate, reasonable, necessary and appropriate. Yet the population of California that passed Prop 65 via referendum should of necessity have been a population of erudite chemists in order to render sound judgment on the Act.  It is beyond reason to believe that was the case.

What is the right level?

C.D. Carrington, a researcher attached to the FDA succinctly explains our concerns about lead in an abstract to one of his published papers:

“Blood lead levels as low as 10 micrograms/dl have been associated with impaired neurobehavioral and cognitive development and electrophysiological deficits in children and reduced gestational age and birth weight in infants. Blood lead levels of 10 micrograms Pb/dl are also of concern in pregnant women because of exposure to the fetus. Blood lead levels of 30 micrograms Pb/dl have been associated with elevated blood pressure and other adverse effects in adults. Thus, the values of 10 and 30 micrograms Pb/dl represent lowest-observed-effects levels for developing and adult populations, respectively.”[6]

But as we have seen, absorptive capability and inhibitory influences in one’s diet reduce the amount of lead that actually enters the body and its circulation. What minimal levels of exposure through diet and environment might result in blood levels described by Carrington as potentially dangerous?

Based largely on Carrington’s work, FDA has determined the following:

FDA Lead Recommendations
Population group Minimum Exposure Limit Safe and tolerable dietary lead uptake (the amount absorbed)
Children infant to 6 years 60 mcg. 6 mcg
Children 7 years and older 150 mcg 15 mcg
Pregnant women 250 mcg 25 mcg
All other adults 750 mcg 75 mcg

As you can see, both the minimum exposure and tolerable absorption levels determined by FDA far exceed the draconian safe harbor level established for lead by Proposition 65.  The exposure level of 60 mcg per day set by FDA for infants and children is 100 times greater than actual, real life exposure calculated from data in the 2010 WHO. A ten pound infant in the U.S. ingests 0.59 mcg per day based on WHO statistics, which is one one-hundredth (1/100th) of the FDA tolerable exposure of 60 mcg. Given that 0.59 mcg actual lead exposure is nearly equal to the Prop 65 safe harbor limit of 0.5 mcg tells us not only that an infant in the United States is not in danger of lead poisoning, but also that Prop 65’s regulations on lead may be superfluous. Given that 0.59 mcg is nearly equal to Prop 65’s 0.5 mcg, and is 100 times lower than the exposure FDA research has determined may result in the lowest potentially dangerous blood lead level for infants (10 mcg per deciliter), implies again that Prop 65 regulation of lead may be unnecessary.

Rechecking our “Criminal” Supplements

If we adjust the absorption percentage in our earlier chart of products in violation of Prop 65, to match the more pessimistic 10% absorption employed by FDA, we find in column #4 that even the worst offending product would deliver slightly more than 2 mcg lead. It should be noted that the plant based sources of ingredients in the products from which the chart’s statistics were compiled would also contain nutrients that inhibit absorption of lead and simultaneously hasten its excretion. Therefore, we can expect absorption of the naturally occurring lead in the products to be less than 10%. But for this exercise, we have shown what a presumed 10% absorption would bring.

Lead content of Prop 65 noticed products (with 10% absorption risk)
Product’s lead content mcg/gm Product dose in gm Gross intake per dose in mcg. % of P65 0.5 µ limit % of normal 500 µ safe limit Absorption in mcg. @10.0% Absorption % of P65 0.5 µ limit Absorption % at normal safety limit of 500 µ
0.49 1.28 0.6272 125.44% 0.125% 0.0627 12.54% 0.013%
1.07 1.28 1.3696 273.92% 0.274% 0.1370 27.39% 0.027%
0.77 1.28 0.9856 197.12% 0.197% 0.0986 19.71% 0.020%
0.39 12 4.68 936.00% 0.936% 0.4680 93.60% 0.094%
0.78 12 9.36 1872.00% 1.872% 0.9360 187.20% 0.187%
0.16 12 1.92 384.00% 0.384% 0.1920 38.40% 0.038%
0.61 12 7.32 1464.00% 1.464% 0.7320 146.40% 0.146%
0.49 12 5.88 1176.00% 1.176% 0.5880 117.60% 0.118%
0.31 12 3.72 744.00% 0.744% 0.3720 74.40% 0.074%
0.7 28.74 20.118 4023.60% 4.024% 2.0118 402.36% 0.402%
0.405 31.34 12.6927 2538.54% 2.539% 1.2693 253.85% 0.254%
0.162 37.57 6.08634 1217.27% 1.217% 0.6086 121.73% 0.122%
0.38 37.57 14.2766 2855.32% 2.855% 1.4277 285.53% 0.286%
0.36 30.17 10.8612 2172.24% 2.172% 1.0861 217.22% 0.217%
0.05 15 0.75 150.00% 0.150% 0.0750 15.00% 0.015%
0.068 15 1.02 204.00% 0.204% 0.1020 20.40% 0.020%
0.088 15 1.32 264.00% 0.264% 0.1320 26.40% 0.026%
0.047 15 0.705 141.00% 0.141% 0.0705 14.10% 0.014%
0.066 15 0.99 198.00% 0.198% 0.0990 19.80% 0.020%
0.064 15 0.96 192.00% 0.192% 0.0960 19.20% 0.019%
0.06 15 0.9 180.00% 0.180% 0.0900 18.00% 0.018%
0.09 15 1.35 270.00% 0.270% 0.1350 27.00% 0.027%
0.11 15 1.65 330.00% 0.330% 0.1650 33.00% 0.033%
0.1 15 1.5 300.00% 0.300% 0.1500 30.00% 0.030%
0.21 15 3.15 630.00% 0.630% 0.3150 63.00% 0.063%


The World Health Organization (WHO) presented more liberal guidelines for the intake of lead than our own FDA prior to 2010. It should be pointed out that WHO has frequently adjusted its advice concerning lead based on accumulating research over the years. Their standard expression of lead recommendations is based on body weight, kilograms of body weight to be precise. That figure had been 3.6 mcg per kilogram for all, children to adults, prior to 2010, but was significantly revised that year. Laid out for comparison with our foregoing FDA chart, we have:

WHO Lead Recommendations, revised 2010
Population group Minimum exposure limit per kg of body weight Total exposure based on body weight
Children 0.6 mcg 1.6 to 40 mcg.
Adults 1.3 mcg 40 to 60 mcg.

WHO determined that their safe levels were in line with the large body of research surrounding lead and its toxicity. Yet even these new, more conservative guidelines from WHO are markedly more liberal than those presented in Proposition 65. For example, a 6 pound infant taking in 1.6 mcg per day is believed by WHO to suffer no ill effects from exposure to more than thirty-two times the level of lead permitted by Prop 65 and 4.6 times the level experienced by a six pound infant in the U.S.

The good

Prop 65 has benefited Californians in many ways by providing incentive for manufacturers to remove listed chemicals from their products. For example, trichloroethylene, which causes cancer, is no longer used in most correction fluids; reformulated paint strippers do not contain the carcinogen methylene chloride; and toluene, which causes birth defects or other reproductive harm, has been removed from many nail care products. In addition, a Proposition 65 enforcement action prompted manufacturers to decrease the lead content in ceramic tableware, and wineries to eliminate the use of lead-containing foil caps on wine bottles.

Dietary supplement manufacturers and their suppliers have similarly responded by demanding ever cleaner, more pure raw materials, and by putting those materials through multiple layers of microbiological and heavy metal analyses. These Good Manufacturing Practices (GMPs) assure the lowest content of naturally occurring heavy metals (i.e lead, cadmium, mercury, arsenic) and have caused the elimination of certain pesticide and solvent residues. The quality of dietary supplements in general has improved since the advent of Prop 65. Yet the level of enforcement actions against dietary supplement companies has accelerated. What could be motivating enforcement?


Who is prosecuting the cases of alleged violation? You might assume that since it is a California state law, then the state Attorney General’s office would be prosecuting the cases. Indeed, the California Attorney General’s office has the power to enforce Proposition 65, but does not often actually become directly involved. Most of the actual enforcement is carried out by private firms, succinctly referred to as “bounty hunters” by defendants and their counsel. Any district attorney or city attorney (for cities whose population exceeds 750,000) may also enforce Proposition 65. But true enforcement falls to a secondary level of enforcers.

Enforcement has been effectively assigned to the people. Any individual claiming to act in the public interest may enforce Proposition 65 by filing a lawsuit against a business alleged to be in violation of the law. Anyone, literally anyone, can set up a company and begin filing suits against supplement companies, alleging the company is in violation. Nearly all Prop 65 litigation in recent years has been initiated by private citizens and their retained law firms. Entrepreneurs have seized on the opportunity, driving dietary supplement companies to settlements through fear of costly legal fees attendant on a protracted court case.

In the current regulatory climate, private firms are bringing Prop 65 inspired lawsuits against any and all dietary supplement companies they can identify, as well as their retailers. One such company is ERC, euphemistically called “Environmental Research Center.” In the 19 months prior to December 2011, it issued 290 separate letters of violation to supplement companies and their retail outlets. On average then, ERC threatened to sue a business every two days during that 19 months. Careful evaluation of products and measured judgment are no longer brought to bear in the search for offending products and supplement companies.

ERC, for example, has moved swiftly to claim its territory. A selection of names– by no means all of them – from their 19 months of activity follows. All were attacked for having allegedly excessive levels of lead in their products.



Betty Lou’s


World Health Products

Ayush Herbs



San Francisco Herb Co.




Sunsweet Growers, Inc.

Nutraceutical Corporation

The Synergy Company

Aloe Life International



Food Science Corp.

Life Extension Foundation

American biologics

Vitamin Shoppe

Genisoy Food co.

Promax Nutrition

ATF Fitness


Country Life

Allergy Research Group

Optimum Nutrition

Health Plus

Atkins Nutritionals

ReLive International


One of the companies above is known throughout the dietary supplement industry for providing raw materials with the lowest lead levels. Another is a major contract manufacturer of nutrition bars whose products are widely sold under many different brand names.

The extensive list of the defendants above points up a most egregious flaw in Prop 65: Specifically, that levels of lead and other substances mandated by Prop 65 are unrealistic. We have looked closely at that issue above, illustrating the foolishly low threshold for lead established by Prop 65. So many companies and representative products are named in ERC’s letters that, if lead were indeed as toxic as Prop 65 enforcement makes it out to be, we would all be dead, or at least as stupid as a Congressman.

A second major flaw in Prop 65 is its allowance for enforcement by private parties. The Attorney General’s office has confessed that it is too busy elsewhere with its limited personnel to police supplements. Private companies have, therefore, rushed to the forefront, realizing a financial boon for themselves under the guise of protecting the public interest.

Turning again to ERC as an example, their standard letters, sent to alleged offenders of Prop 65, state:

Note item (2). The plaintiff, ERC stands to receive 25% of the penalty. Hence, there is motivation to extract as much of a fine, calculated against sales of the products, as possible. Several respected manufacturers of the highest quality supplements and a few retailers in the industry have chosen to pay $50,000, $80,000, $120,000 and more to resolve these cases.

Considerations for Today

The regulatory situation in California has degraded to the point where any company that markets dietary supplements will eventually be attacked by entrepreneurial enforcers. Indeed, a “bounty hunters” purpose is to enrich themselves by exercising a seriously flawed piece of legislation. We have a state law enforced by non-state entities. Profit becomes the driving motivation behind enforcement at the final expense of consumers of health products.

The “safe harbor” exposure for lead according to Prop 65 is 0.5 micrograms of lead per day. The allowable lead level is absurdly low. It could be that simply breathing air in Los Angeles violates Prop 65. Certainly we have seen that eating food does violate Prop 65. The naturally occurring amount of lead in food and botanicals (both fresh, dried or powdered) places them in violation of Prop 65 guidelines, and makes eating each plate of dinner a criminal exercise.

The saving piece of wisdom built into the legislation allows an exemption to the law for “naturally occurring” levels of heavy metals in foods and dietary supplements made from them. Yet no dietary supplement company has as yet satisfactorily proved that the amount of lead in a product was not placed there through any addition or though any degree of negligence; that its presence is instead a natural part of the ingredients. Indeed, all food contains some lead, arsenic, iron, cadmium and/or other heavy metals. So why is it so difficult to successfully avoid prosecution by satisfying the “naturally occurring” clause? It could simply be so impossible because those prosecuting Prop 65 cases are interested in settling cases for money.

The Message

It is important for the retail community and its consumers to understand the impracticality of Prop 65 as it applies to dietary supplements. Relative to lead, the Act sets goals for purity that did not have to be set in the first place, and cannot be met in the real world. Nor can a 0.5 mcg per day intake be met by most dietary supplement formulas fashioned from natural ingredients, unless, of course, recommended dosages of those supplements are greatly reduced. If that must be done, then efficacy of the supplement may be lost.

[1] Carrington CDBolger PM. An assessment of the hazards of lead in food, Regul Toxicol Pharmacol. 1992 Dec;16(3):265-72.

[2] Evaluation of Certain Food additives and Contaminants, Seventy-third meeting of the Joint FAO/WHO Expert Committee on Food Additives, p. 167, Geneva, 8-17 June, 2010

[3] Evaluation of Certain Food additives and Contaminants, Seventy-third meeting of the Joint FAO/WHO Expert Committee on Food Additives, p. 171, Geneva, 8-17 June, 2010

[4] Evaluation of Certain Food additives and Contaminants, Seventy-third meeting of the Joint FAO/WHO Expert Committee on Food Additives, p. 172, Geneva, 8-17 June, 2010

[5] Evaluation of Certain Food additives and Contaminants, Seventy-third meeting of the Joint FAO/WHO Expert Committee on Food Additives, p. 173, Geneva, 8-17 June, 2010

[6] Carrington CDSheehan DMBolger PM, Hazard assessment of lead, Food Addit Contam. 1993 May-Jun;10(3):325-35.

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