What is a pesticide?
Broadly defined, a pesticide is any agent used to kill or control any
pest (1, 2). Pests can be insects,
rodents or birds, unwanted plants (weeds), fungi, or microorganisms such as
bacteria and viruses. Though often misunderstood to refer only to
insecticides, the term pesticide also applies to herbicides, fungicides,
microbiocides, rodenticides and various other substances used to control
pests. Under United States
law, a pesticide is also any substance or mixture of substances intended
for use as a insect or plant growth regulator, insect mating disruptor or
egg sterilant, defoliant, or desiccant. Many household products are
pesticides, such as cockroach sprays and baits, rat poisons, pet flea
collars, products that kill mold and mildew, and kitchen disinfectants.
Definition of Terms
More About "Inert" Ingredients
Definition of Terms
In evaluating pesticide information, several distinctions associated
with pesticides are quite important.
ingredients are the specific chemicals contained in a
pesticide product that are designed to kill a particular pest. By law,
the active ingredient must be identified by name on the label together
with its percentage by weight.
ingredients are commonly mixed with the active ingredients to create
a formulated pesticide product. See below for more information
on "inert" ingredients.
pesticide products are the form of the pesticide that is available
to the consumer, grower, or pest control applicator, and may take the
form of sprays, bait stations, fly strips, flea collars, dusts, etc.
About "Inert" Ingredients
Inert ingredients include solvents, emulsifiers, spreaders, and other
substances mixed into pesticide products to increase the effectiveness of
the active ingredients, make the product easier to apply, or to allow
several active ingredients to mix in one solution. An inert ingredient is
simply any ingredient in the product that is not intended to affect a
target pest (3). Inert ingredients can be as much as
99% of pesticide products. Both U.S. EPA and California Department of
Pesticide Regulation require pesticide manufacturers to identify inert
ingredients in their products but do not disclose this information to the
general public because the pesticide industry considers product
formulations trade secrets, protected by law.
Many inert ingredients have adverse health effects and may themselves be
used as pesticides. In fact, at least 382 chemicals on the U.S. EPA list of
pesticide inert ingredients are or were once registered as pesticide active
ingredients (4). Eight inert ingredients are considered
by U.S. EPA to be "of toxicological concern" and another 75 are
"potentially toxic." The U.S. EPA strongly encourages registrants
(manufacturers and companies who buy and repackage pesticides for market)
to substitute less toxic substances for these hazardous inerts in pesticide
products. Nevertheless, a large but unknown quantity remain in use (5).
While the identity of specific "inerts" in a particular
pesticide product is not available to the public, it is possible to
estimate the quantity of inert ingredients released into the environment
using California Pesticide Use Reporting (PUR) data. In 1998, a total of
215 million pounds of pesticide active ingredients and 134 million pounds
of inert ingredients were applied in California.
Pesticide products used in urban areas typically contain more inerts than
The Northwest Coalition for Alternatives to Pesticides has an extensive
web site on "inert" ingredients and their campaign to make them
is a Pesticide?, U.S. EPA. Viewed on April 8, 2005.
is a Pesticide?, California
Department of Pesticide Regulation. Viewed on April 8, 2005.
Ingredients in Pesticide Products, U.S. EPA. Viewed on April 8, 2005.
Marquardt, C. Cox, and H. Knight, Toxic
Secrets: "Inert" Ingredients in Pesticides 1987-1997,
Northwest Coalition for Alternatives to Pesticides and Californians
for Pesticide Reform (San Francisco, 1998). Viewed on April 8, 2005.
of Other (Inert) Pesticide Ingredients, U.S. EPA.
Viewed on April 8, 2005.
Disclosure Campaign, Northwest Coalition
for Alternatives to Pesticides web site. Viewed
on April 8, 2005.
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Last updated April 7, 2005 .