Inert Ingredients: Are They Really Benign?

Journal of Pesticide Reform (Vol. 19, No. 2)
Northwest Coalition for Alternatives to Pesticides
Last Updated: Tuesday, July 10, 2007

Inert ingredients are present in virtually all pesticide products. They are substances added to pesticides to make them more potent or easier to use, but their identities are often claimed as confidential and they have only minimal testing requirements.

Despite this lack of testing, many inerts pose known hazards. About a quarter of inerts have already been classified as hazardous by state, federal, and international agencies.

Our national pesticide law classifies pesticide ingredients into two categories, "active"₁ and "inert." ₂ Active ingredients are those that are designed to kill or damage a pest. Inerts are all other ingredients used in pesticide products and are added to active ingredients to make the pesticide more potent or easier to use. Inert ingredients are not inert in the usual sense of the word; often they are neither chemically, biologically, nor toxicologically inert.₃

Pesticide manufacturers claim that the identity of many inert ingredients is confidential business information and will not publicly disclose them. Under the Freedom of Information Act, the public can get information from the U.S. Environmental Protection Agency (EPA) about the inerts in a pesticide product unless the manufacturer proves that the information is confidential.₄

Inert Hazards

Because there are only "minimal" testing requirements for inerts, EPA has little information about their hazards. Of the over 2300 substances EPA believes are used as "inerts" in pesticide products, EPA classifies most (over 1700) as "of unknown toxicity"₅ because EPA’s Office of Pesticide Programs does not have adequate information about their potential hazards.

However, there is clear evidence that many inerts pose significant toxicological and environmental hazards. State, federal, and international agencies have classified 26 percent of them (about 600 chemicals) as hazardous.₆ Specific inert ingredients have well-known hazards. Examples include the following:
Crystalline silica is a carcinogen_.7
Nonyl phenol ethoxylates cause destruction and marked deterioration of fish gills.₈
Ethylbenzene has caused fetal loss, birth defects, and testicular cancer.₉
Xylenes cause vomiting, impaired short-term memory, and reduced fertility.₁₀
Trimethylbenzenes cause bronchitis, fatigue, and dizziness.₁₁
Chlorofluorocarbons cause destruction of stratospheric ozone.₁₂

Why Is Public Disclosure Important?

It is impossible for pesticide users, whether they are government agencies, businesses, or homeowners, to accurately understand the hazards of a pesticide product they are proposing to use if they don’t know its ingredients.

"Inert" ingredients also pose a crucial ethical issue. We are all exposed to pesticides on a daily basis, whether or not we like that exposure. Given this situation, the very least we can do is to insure that we have complete, easily and publicly accessible information about all of the ingredients in pesticide products.

Visit the Northwest Coalition for Alternatives to Pesticides Inerts Ingredients Disclosure Campaign  for more information.

References

1. Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Sec. 2(a).
2. FIFRA Sec. 2(m).
3. U.S. EPA. Office of Pesticide Programs. 1997. Pesticide regulation notice 97-6. Washington, D.C.
4. Northwest Coalition for Alternatives to Pesticides, et al v. Browner. 941 F. Supp. 197 (D.D.C. 1996).
5. U.S. EPA. 2002. List of inert pesticide ingredients.
6. S. Marquardt, C. Cox, and H. Knight. 1998. Toxic secrets: "Inert" ingredients in pesticides: 1987- 1997. Northwest Coalition for Alternatives to Pesticides.
7. International Agency for Research on Cancer. 1999. Overall evaluations of carcinogenicity to humans.
8. Pärt, P., O. Svanberg, and E. Bergström. 1985. The influence of surfactants on gill physiology and cadmium uptake in perfused rainbow trout gills. Ecotoxicol. Environ. Safety 9:135-144.
9. U.S. Dept. of Health and Human Services. Public Health Service. Agency for Toxic Substances and Disease Registry. 1997. Toxicological profile for ethylbenzene. Atlanta, GA, Sept.
10. U.S. Dept. of Health and Human Services. Public Health Service. Agency for Toxic Substances and Disease Registry. 1997. Toxicological profile for total xylenes. Atlanta, GA, Aug.
11. Sittig, M. 1991. Handbook of toxic and hazardous chemicals and carcinogens. 3rd edition. Vol. 2. Park Ridge, NJ: Noyes Publications. Pp. 1161-1162.
12. U.S.EPA. 1995. Ozone-depleting substances.

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