APPENDIX II-N:  Inerts and Piperonyl Butoxide:


More on "inerts".(Health Risks and Environmental Issues)(Piperonyl Butoxide)

From: Townsend Letter for Doctors and Patients  |  Date: 7/1/2004  |  Author: Williams, Rose Marie

"Inert" Misnomer

Last month's article on "inert" ingredients illustrates how the word is improperly used by the pesticide industry. Current law only requires labels to list the "active" ingredient--the chemical specifically targeted to kill a particular insect, weed, mold, or rodent. The "active" ingredient may be as little as 1% to 15% of a product. The remaining 85% to 99% of the formulation is made up of ingredients that are listed as "inerts," but which often consist of chemicals that are classified as known, or suspected carcinogens. Many chemicals listed as "inerts" in one product are used as the "active" ingredient in other pesticide formulations. The average consumer is unaware that the word "inert" on product labels is a complete misnomer. Far from being inactive or non--reactive, "inert" ingredients in pesticide products may include highly toxic chemicals. (1)


Of the 2,300 substances used as "inerts," over 1,700 are of unknown toxicity, 209 are hazardous air and water pollutants, 21 are known or suspected carcinogens, and 127 are listed as occupational hazards according to the 1998 report, Worst Kept Secrets: Toxic Inert Ingredients in Pesticides." (2)

The states of New York, Alaska, Connecticut, Massachusetts, Minnesota, New Hampshire, Wisconsin, Arizona, Illinois, and the Territory of Guam have been joined by numerous environmental organizations in filing a suit against the United States Environmental Protection Agency (EPA) to require disclosure of all ingredients on pesticide product labels, not just the "active" ingredient. Industry claims confidentiality rights are necessary protection from competitors, but modern laboratory technology using reverse engineering can easily discern product ingredients. Therefore, it is only the consumer who remains uninformed about the actual risks associated with the chemical contents of a pesticide product. EPA has been stalling on the issue of listing all ingredients on product labels, hoping for a mutual agreement between industry and health advocates. Neither side has been willing to budge. EPA decided in favor of a "voluntary" disclosure, which is what industry was pushing for all along. Once again the consumer loses. (1,2)


Most Americans believe that pesticide products have been thoroughly tested for health risks, and that approval for sale implies product safety. This writer was a typically naive consumer who, thanks to many environmental organizations devoted to alerting the public about pesticide hazards, has learned a great deal about how industry manipulates science and government for personal gain, at the expense of public health.

After a half-century of nearly indiscriminate use of toxic pesticides in agriculture, forestry, roadsides, golf courses, parks, playgrounds, workplaces, schools, hospitals, homes and yards, the synergistic effect of multiple exposures to humans and wildlife is finally being questioned. It was assumed the combined effects of exposure to a group of pesticides were simply additive. A study done as far back as 1957 demonstrated this to be untrue. Researchers expected results from exposure to the organophosphate insecticide, ethylpnitrophenyl benzenethiophosphate (EPN) and malathion would be additive, but instead found a 10-fold synergistic effect in rats and a 50-fold synergistic effect in dogs for acute toxicity when these toxins were administered simultaneously. Synergy refers to the interaction of chemicals. (3)

West Nile Virus (WNV), spread by mosquitoes, first appeared in a few sections of New York City during the summer of 2000. The disease can be fatal to immune compromised individuals, but generally produces only weak flu-like symptoms, or no symptoms at all in a healthy population. The health agencies and the mayor took immediate action to blanket certain neighborhoods with malathion, ignoring the protests of many citizens. Residents were further advised to use personal insect repellants with DEET, a hazardous neurotoxic chemical whose health risk to children was being reassessed. (4)

EPA subsequently required new DEET labels to carry more stringent health warnings. Malathion was also under EPA review, even while it was being sprayed aerially and trucks were fogging many neighborhoods and parks. Before the year was up EPA decided to restrict the use of malathion for similar applications. Informed consumers complained that unwarranted exposure to malathion posed a greater health risk than did West Nile Virus, and that no agency was conducting ongoing studies about future health problems related to the pesticide exposures. (4,5) During subsequent summers WNV moved beyond New York. Some states implemented similar pesticide spray programs, while other municipalities chose more conservative methods of mosquito control.

In addition to the lack of disclosure about toxic "inert" ingredients, the American consumer remains unaware of the dangers of synergistic effects of exposure to more than one toxic chemical at a time. The chemical industry and the US EPA assure us that current testing protocol for pesticide chemicals is adequate for protecting human health. This is untrue, and we should never assume there is any degree of safety in using pesticide products. (1)

After decades of ignoring children's unique vulnerability to pesticide and chemical exposure, EPA has recently been mandated to consider safety issues as they pertain to children's health. But, children's vulnerability continues to be ignored regarding the listing of all chemical ingredients on product labels. Furthermore, it is astonishing to learn that product safety is judged only on the basis of researching the "active" ingredient in a product. Testing of "inert ingredients" is not required, nor are health risks associated with "inert" ingredients considered, even though many chemicals used as "inerts" are themselves highly toxic.

Another area of omission by the regulatory agencies is the synergistic action of exposure to more than one chemical at a time, be it in the same product, or from more than one product. Certain combinations of chemicals can increase the toxicity of one or more components, or even lengthen the duration of toxicity beyond the normal breakdown period.

In the 1960s and early 1970s, Samuel Epstein, MD, then with The Children's Cancer Research Foundation in Boston, and Keiji Fujii, MD, with the National Institute of Hygienic Sciences in Tokyo published a series of papers highlighting the increased carcinogenicity between two chemicals used in combination, even at subcarcinogenic levels, or when applied as far apart as 200 days. Government did not pick up the ball on this, despite general consensus that Americans are continually facing multiple exposures and health risks from a number of chemical combinations from multiple pesticides, pharmaceuticals and over-the-counter (OTC) drugs. (3)

Duke University Medical Center in Durham, NC, has been conducting research on the synergistic effects of DEET and permethrin (the pesticide of choice following the restricted use of malathion in mosquito abatement in the US). These two chemicals were used during the Gulf War with the addition of pyridostigmine bromide, a drug given to soldiers as a precaution against toxic gas warfare agents. Studies showed no negative effects when the chemicals were administered alone, but in combination the test animals displayed neurological deficits consistent with symptoms suffered by Gulf War veterans. (3)

Piperonyl Butoxide

The chemical industry may deny negative health risks from synergistic action, but employs the principle of synergy when adding specific "inert" ingredients to pesticide formulations to increase the toxicity of, and to prolong the potency of "active" ingredients. Piperonyl Butoxide (PBO) is a frequently used synergistic chemical. It is one of the most commonly used ingredients in household pesticide products. PBO inhibits the activity of a family of enzymes called P450s, which have many functions including the breakdown of toxic chemicals and transformation of hormones. It interferes with cholinesterase activity and can increase the neurotoxicity of other compounds such as methylmercury. (6)

Since 1965 Piperonyl Butoxide (BPO) has been classified by the EPA as a "probable human carcinogen" because it caused liver tumors and cancers in laboratory tests. A study done by the manufacturer of PBO found it to cause atrophy of testes in male rats. Behavioral changes, such as a decrease in home recognition behavior in the offspring of exposed mothers were also noted. A variety of hormone-related organs including thyroid glands, adrenal glands, and the pituitary gland are affected by PBO. It interferes with human lymphocytes (blood cells that help fight infections). (6)

Exposure to PBO may produce symptoms of nausea, diarrhea, and breathing difficulty. It can damage the larynx, liver, kidneys, circulatory system, immune function, and cause genetic mutation. As a synergist, PBO can increase the carcinogenicity of other cancer-causing chemicals, though it continues to be listed as an "inert" ingredient in many pesticide formulations. When used in aerosols and "bomb" treatments PBO contaminates the air. PBO is used in agriculture and is regularly found on spinach, peas, sweet potatoes, tomatoes, peaches, squashes, strawberries, bell peppers, grapes and pineapples. (6)

Terbutaline (Pre-term Labor Drug)

A drug commonly prescribed to halt pre-term labor and stave off premature birth might leave the brains of children susceptible to other chemicals ubiquitously present in the environment, according to research conducted on lab animals at Duke University. Rats exposed to the pre-term labor drug, terbutaline, were found to suffer greater brain cell damage upon secondary exposure to chlorpyrifos than those not exposed to terbutaline. The double exposure caused damage to brain regions known to play a role in learning and memory, which might explain why children of mothers who were given terbutaline suffer cognitive deficits. (7)

The work highlights the synergistic and unpredictable effects that multiple chemical exposures can have on the brain, according to senior author of the study, Theodore Slotkin, PhD, professor of pharmacology and cancer biology at Duke. "The adverse effects of sequential exposure to the two compounds on certain brain characteristics were more than the sum of the two agents' independent effects," claimed Slotkin. (7)

Trusting the Experts

Navigating the information byways on environmental and health issues is full of pitfalls, as any health consumer can attest to. For years, American women were told by establishment health experts that Hormone Replacement Therapy (HRT), prescribed for menopausal symptoms, was also good protection against heart disease. Warnings of increased cancer risk from a small number of medical experts outside the loop were ignored. The establishment experts were wrong again. HRT has been shown to increase a women's risk of cancer, and heart disease as well. Consumers must choose which experts to rely on for accurate information--government/industry scientists, or independent sources.

I will cite two instances that proved to be real eye opening experiences for this emerging health and environmental advocate. After much political lobbying during the 1990s, Long Island (New York) breast cancer activists, suspicious of a pesticide connection to their disease, promoted a bill to have New York track the amount of pesticides used in the state. A new department was set up at Cornell University to look more closely at the pesticide/breast cancer connection. At one of the Cornell forums a panel of experts was presenting information on pesticides and lab studies. The question, "What are 'inert' ingredients?" was asked of one of the prominent scientists on the panel. The expert to whom the question had been specifically directed, responded that, "Inerts are mostly fillers, like water." Shocked by such a misinformed answer to a question of major scientific relevance made this writer even more skeptical of establishment experts.

A second impressionable event occurred at another meeting, which included a few advocates and experts from the New York State Department of Environmental Conservation (DEC), on the issue of pesticides and health risks. A few weeks before the meeting a recent environmental journal carried an article about the pesticide, Dicofol, containing the banned chemical DDT as an "inert" ingredient. As usual, the experts were attempting to reassure us of the safety of pesticide use based on current information. When asked about DDT being used as an "inert" ingredient in Dicofol, the DEC expert said that was not possible, but promised to look into it. A couple of weeks later I received a call confirming that DDT had indeed been used as an "inert" ingredient in Dicofol as late as the 1980s. How many consumers would suspect that DDT was still being used on their food nearly two decades after it had been banned, and that it was hidden as an "inert" ingredient, no less? Dicofol is used to control mites on grapes, pears, apples, melons, peppers, tomatoes, cucumbers, squash, pumpkins, citrus fruit, pecans, walnuts, mint, Christmas trees, and hops.

"Interts" Warrant New Branch

The EPA Office of Pesticide Programs is planning to create a separate regulatory branch in the coming year to deal specifically with "inert" ingredients in pesticides. Certainly a positive move since EPA has accumulated a ten-year backlog of "inert" approvals. Industry is pushing for EPA to catch up as it awaits the approval for new "inert" ingredients in new pesticide products. (2)

The recent implementation of the Food Quality Protection Act requires EPA to finally reassess tolerances for hundreds of "inerts" used on food, by August 2006, regarding the toxicity to children. However, no staff and no funds have been allocated for the new agency. Once again government attempts to protect our children from toxic chemicals proves to be woefully inadequate. (2)


1. Williams, RM, "What Is Meant By "Inert" Ingredients?" TLfDP, #251, June 2004.

2. "Stand Alone Branch for Inerts Coming to EPA," The News Bulletin of Beyond Pesticides--Tech Report, NCAMP, 202-543-5450, March 2004.

3. Kepner, J, "Synergy: The Big Unknowns of Pesticide Exposure," Pesticides and You, NCAMP, 202-543-5450, Vol. 24, No. 1, Winter 2003/2004.

4. Williams, RM, "DEET Alert!," TLfDP, #204, July 2000.

5. Williams, RM, "Malathion--Cure Worse Than Disease," TLfDP, #202, May 2000.

6. Cox, C, "Piperonyl Butoxide," Jrnl. of Pesticide Reform, NCAP, 541-344-5044, Vol. 22, No. 2, Summer 2002.

7. Beyond Pesticides' Daily News Headline, NCAMP, mtaylor@beyondpesticides, April 15, 2004.

RELATED ARTICLE: Video Presentation: "Health Risks and the Environment"

by Rose Marie Williams, MA

president of the Cancer Awareness Coalition, Inc.

P.O. Box 533, New Paltz, New York 12561 USA

Cost: $20.00 (free postage within US).

Specify Video or DVD (60 min.).

Check or Money Order made to the Cancer Awareness Coalition, Inc.

How environmental risk factors affect health more than inherited genes is discussed in this candid talk by health advocate, Rose Marie Williams, who also offers suggestions about reducing toxic exposure in and around the home. Included are contact numbers for inexpensive water testing, pesticide information, useful books and pamphlets.

The Cancer Awareness Coalition, Inc., is a 501[c](3) grassroots health and environmental organization dedicated to--raising awareness about health risks associated with pesticides and other pollutants--encouraging use of safer practices--promoting legislation that protects public health. Video sales support this mission.

by Rose Marie Williams, MA

156 Sparkling Ridge Road * New Paltz, New York 12561 USA

845-255-0836 * Fax 845-255-5101 *



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