What is an inert ingredient?

Our national pesticide law classifies pesticide ingredients into two categories, "active"(1) and "inert."(2) Active ingredients are those that are designed to kill. Legally, they are defined as chemicals that "destroy, prevent, repel, or mitigate"(1) any pest. Inerts are all other ingredients used in pesticide products(2) and are added to active ingredients to make the pesticide more potent or easier to use. Solvents, surfactants, and carriers are examples of the kinds of ingredients commonly used as inerts.(3) Inert ingredients are not inert in the usual sense of the word; they are neither chemically, biologically, nor toxicologically inert.(4) 

Does the public know the inert ingredients in most pesticide products?

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 request information from the U.S. Environmental Protection Agency (EPA) about the inerts in a pesticide product and it will be provided unless the manufacturer makes a confidentiality claim.(5)

Are inert ingredients regulated differently than active ingredients?

In brief, the answer to this question is yes. Under amendments to our national pesticide law passed in 1972, active ingredients are required to be tested for a battery of toxicological and ecological problems.(6)  Since 1972, EPA has been attempting to bring testing for each registered active ingredient up to these standards.(6)  Inert ingredients, on the other hand, were not subject to testing requirements until 1987.(7)  The requirements for health and safety testing of inerts which EPA established at that time were called "minimal"(7) even by EPA. They did not include tests for the following serious hazards:(7)

the ability to cause cancer

the ability to adversely affect fertility and reproduction

the ability to damage the nervous system

In addition, EPA requires very little testing for the potential hazards of the combination of active and inert ingredients,(8) even though humans and the environment are actually exposed to this chemical cocktail when a pesticide is used. Does the combination cause cancer? Does the combination cause birth defects or other reproductive problems? Does the combination cause adverse effects following long-term exposure? None of these questions can be answered based on current testing requirements.(8)

How much information does EPA have about the hazards of inert ingredients?

The lack of testing requirements means that EPA has very little information about the hazards posed by inerts. Of the over 2300 substances EPA has identified as inerts in pesticide products,(9) EPA classifies most (over 1700) as "unknown toxicity"(9) because EPA's Office of Pesticide Programs does not have adequate information about their 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 (610 chemicals) as hazardous.(10) Specific inert ingredients have well-known hazards. Examples include the following:

Crystalline silica is classified as a carcinogen by the International Agency for Research on Cancer.(11) 

Nonyl phenol ethoxylates cause destruction and marked deterioration of fish gills.(12) 

Ethylbenzene has caused fetal loss, birth defects, and testicular cancer.(13)

Xylenes cause vomiting, mild liver toxicity, impaired short-term memory, and reduced fertility.(14) 

Trimethylbenzenes cause bronchitis, fatigue, and dizziness.(15) 

Cumene causes narcotic effects and depression of the central nervous system.(16) 

Chlorofluorocarbons cause destruction of stratospheric ozone.(17)

Why is public disclosure of the identity of inert ingredients 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 donít know its ingredients. Our national pesticide law, the Federal Insecticide, Fungicide and Rodenticide Act, requires EPA to regulate pesticide use to prevent "unreasonable adverse effects on the environment." EPA can't do this accurately if the ingredients of the pesticide in question and their hazards are unknown.

What are the key elements of NCAP's lawsuit?

In 1996, a federal district court ruled that under the Freedom of Information Act, EPA must provide the public with documents that identify the inert ingredients in pesticide products unless pesticide manufacturers can show that disclosure will cause them competitive harm. The justifications must be specific to the product and ingredient under discussion.(5) The court ruling gave the public access to information about the identity of inert ingredients in pesticide products for the first time. NCAP was the lead plaintiff in this lawsuit.

Since 1996, however, EPA has routinely allowed pesticide manufacturers to claim that the documents describing how manufacturers justify these confidentiality claims are themselves confidential. Public interest groups and the concerned public had to accept EPA's assurances that claims were justified and that the agency was complying with the 1996 court decision.

In 1999, NCAP filed a lawsuit alleging that EPA's routine acceptance of these confidentiality claims was contrary to the Freedom of Information Act. On March 28, 2003, the court ruled in NCAP's favor. This important step gives NCAP and others the opportunity to make sure that EPA and pesticide manufacturers comply with the law.

References

1. Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Sec. 2(a).
2. FIFRA Sec. 2(m).
3. U.S. EPA. Office of Public Affairs. 1987. Environmental news. Washington, D.C., Apr. 21.
4. U.S. EPA. Office of Pesticide Programs. 1997. Pesticide regulation notice 97-6. Washington, D.C. www.epa.gov/oppmsd1/pr97-6.html.
5. Northwest Coalition for Alternatives to Pesticides, et al v. Browner. 941 F. Supp. 197.
6. U.S. General Accounting Office. 1993. Pesticides: Pesticide reregistration may not be completed until 2006. Washington, D.C., May.
7. U.S. EPA. 1987. Inert ingredients in pesticide products; Policy statement. Fed. Reg. 52(77):13305-13309, Apr. 22.
8. Code of Federal Regulations 40 § 158.340.
9. U.S. EPA. 1998. List of inert pesticide ingredients. www.epa.gov/opprd001/inerts/inerts.xls.
10. S. Marquardt, C. Cox, and H. Knight. 1998. Toxic secrets: ìInertî ingredients in pesticides: 1987-1997. Northwest Coalition for Alternatives to Pesticides.
11. International Agency for Research on Cancer. 1999. Overall evaluations of carcinogenicity to humans. http://193.51.164.11/monoeval/crthall.html.
12. 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.
13. 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.
14. 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.
15. Sittig, M. 1991. Handbook of toxic and hazardous chemicals and carcinogens. 3d edition. Vol. 2. Park Ridge, NJ: Noyes Publications. Pp. 1161-1162.
16. Sigma Chemical Co., Aldrich Chemical Co., and Fluka Chemical Co. 1994. Material Safety Data Sheet: Cumene. St. Louis MO, Milwaukee WI, and Ronkonkoma NY.
17. U.S.EPA. 1995. Ozone-depleting substances. www.epa.gov/ozone/title6/sec602.htm.