About 85 percent of American homes maintain an average inventory of 3
to 4 pesticide products, including pest strips, bait boxes, bug bombs,
flea collars, pesticidal pet shampoos, aerosols, granules, liquids and
dusts. Roughly 70 million households make more than 4 billion
pesticide applications per year, an average of 57 applications per
household per year. According to the National Home and Garden Pesticide
Use Survey by U.S. Environmental Protection Agency (EPA), almost 39
percent of households use insecticides because they have a major insect
problem. However, 37 percent of all U.S. households treat for insects
even when there is not a major problem.
A 1994 study of pesticide labels published in the JOURNAL OF THE
AMERICAN OPTOMETRIC ASSOCIATION found that it requires an 11th-grade
cognitive reading level to understand a pesticide label, which means
that 40 to 50 percent of the general population cannot read and
understand the directions on a pesticide product label, even if all
members of the public had the necessary 20/30 visual acuity to read the
Nationwide in 1993, 140,000 pesticide exposures, 93 percent of which
involved home use, were reported to poison control centers. About 25
percent of these exposures involved pesticide poisoning symptoms. Over
half of all reported exposures involved children under age 6.
According to toxicologist William Pease of the University of
California-Berkeley School of Public Health, indoor use of pesticide
products in the home is the main source of exposure for children.
Furthermore, Pease says exposures from household use exceed (but of
course are added to) those from pesticide residues in food.
There are over 20,000 different household pesticide products containing
over 300 active ingredients and up to 1700 inert ingredients. Household
pesticides may contain more than 99 percent inert ingredients. Active
ingredients are the ingredients that are listed on the product label
and are regulated by law. Inert ingredients are not listed on the label
and are not regulated.
Section 2m of the Federal Insecticide, Fungicide, and Rodenticide Act
(FIFRA) --the nation's pesticide control law --states, "The term 'inert
ingredient' means an ingredient which is not active." In actual
practice, pesticide manufacturers decide what to call inert and what to
designate as an active ingredient subject to EPA regulation. This has
produced a situation where ingredients considered active and regulated
by the EPA in some pesticide products are, in other pesticide products,
unregulated, inert ingredients, missing from the label.
In 1991, the Inspector General of the EPA issued a report on inerts in
household pesticides [U.S. EPA Office of the Inspector General, INERT
INGREDIENTS OF PESTICIDES (audit report No. E1EPF1-05-0117-1100378,
September 27, 1991)]. The report identified 4 categories of inerts:
** 300 inerts are "generally recognized as safe." This category
includes dextrose, ethanol, fish meal, lard, olive oil, water, and
** 68 inerts are "potentially toxic." Examples include petroleum
hydrocarbons, toluene, xylene, and methyl bromide.
** 56 inerts are "toxic." These ingredients yield evidence of
carcinogenicity, adverse reproductive effects, neurotoxicity, or other
chronic effects, or birth defects in laboratory animals or humans.
Examples: aniline, asbestos, benzene, carbon disulfide, chloroform,
formaldehyde, hexachlorophene, lead, cadmium, and mercury oleate.
** 1300 inerts have "unknown toxicity." The EPA Office of Inspector
General (the EPA's internal police force) says, "EPA knows little or
nothing about the adverse effects of most of these inert ingredients.
Some data may exist for the inert ingredients of unknown toxicity, but
EPA has not yet evaluated the data to determine the effects." Examples
include barium sulfate; epoxy resin; styrene acrylic copolymer; sodium
nitrite; thymol; lithium chloride; naphthalene; polyethylene
terphthalate; D & C Red #37; malathion; kerosene; coal tar; asphalt;
Freon 114; and sulfuric acid. Gathering information about the health
effects of these inerts presently has low priority at EPA, receiving
less than 1 percent of the Office of Pesticide Programs' budget.
Furthermore, EPA has no specific procedures or time frames for ensuring
that these inerts are reviewed, according to the EPA Office of
Inspector General. "Until these reviews are completed, users are
unaware of potentially toxic inert ingredients contained in certain
pesticide products. The use of these pesticide products may be
jeopardizing human health and the environment," the EPA Office of
Inspector General states.
By law, inert ingredients are not listed on pesticide product labels.
Only "active" ingredients are listed on labels. Furthermore, government
officials are forbidden by law from revealing the inert ingredients in
pesticide products. "Inert ingredients are confidential information. If
we were to disclose that information we could be prosecuted for it and
imprisoned," says Louise Mehler, a physician and program director of
California EPA's Worker Pesticide Illness Surveillance Program. Mehler
says some inert ingredients "are sometimes of real toxicological
significance" whereas they "could also be just water." Although inert
ingredients are secret by law, it is widely believed that pesticide
companies know their competitors' inert ingredients. "The chemists here
say that since the invention of the mass spectrometer anybody who wants
can really find out," says Mehler.
U.S. government evaluation of pesticides has focused rather narrowly on
cancer, and that there is evidence that pesticide exposures can cause
other health effects besides cancer. Specifically, damage to the immune
system (including, but not limited to, allergic reactions) and the
central nervous system are known to result from pesticide exposures.
For example, John Bucher, acting chief of the toxicology branch of the
National Institute of Environmental Health Sciences, is quoted saying,
"We have spent an enormous amount of time in pesticides with cancer
assessments. [But] we could be missing the boat on the potential
effects on the immune system." He goes on to note that subtle effects
on the nervous system are almost never studied: "We almost never see
anything on learning, memory, and potential psychological effects of
exposures," says Bucher. "You can't ask a test animal for the kind of
information that you can ask people. So you can't adequately study some
of these things with animal models," he said.
The most sensitive creatures are human fetuses and infants, according
to Dr. Sheila Zahm of the National Cancer Institute. She recommends
that pregnant women should avoid exposure to any pesticides. The
rapidly-growing fetus may be particularly susceptible to mutagenesis
[genetic damage], chromosomal aberrations, and carcinogenesis, Zahm
says. She points out that infants crawling on carpets may be exposed to
lawn chemicals tracked indoors, and that such chemicals may endure much
longer indoors than they would outdoors exposed to rain and sunlight.
William Pease from Berkeley asks whether some pesticides are worth the
hazards: "Because of the difficulties in controlling how the end-user
uses the product, and knowing that at least some will become ill, as we
are currently seeing adverse effects, the question in our mind, since
there are alternative means of treating many pests, is if we should
even recommend some of these products when we know there are
Federal pesticide authorities have far to go before they have fully
evaluated the health effects of pesticide products currently on the
market, and to which millions of American families, including children,
are exposed routinely and repeatedly each year.
EPA knows little or nothing about the toxic characteristics of most of
the 'inerts' that make up the bulk of most household pesticides.
Furthermore, government officials are prohibited -- under penalty of
prison sentence --from revealing to the public what they DO know about
inert ingredients. Meanwhile, this enforced secrecy about inerts does
not prevent a pesticide producers' competitors from learning which
inerts are being used. Only the public is prohibited from learning this
Pesticides can affect the immune system, the central nervous system,
and other bodily systems as well, such as the endocrine (hormone)
system and the genes. Damage to the genes may be inherited by the next
generation, and then passed on to subsequent generations. These
important non-cancer effects of pesticides have hardly been studied by
government health authorities.
So little is known about the health effects of pesticides, and the
"inerts" that are integral to them, that full health risk assessments
for pesticides cannot be completed in any meaningful sense. At present
rates of study, it will take centuries or longer before sufficient
information has been gathered. Therefore, assurances of safety from
most pesticide exposures cannot be based on sound scientific evidence,
but more on wishful thinking, or guesswork.
Although the purpose of labeling is to allow consumers to protect
themselves, this purpose is not served by present labeling practices
because (a) much of the public hasn't the skills necessary to read a
pesticide product label; and (b) so-called 'inert' ingredients, which
may not be inert in the normal sense of that word, and which can make
up more than 99 percent of a pesticide product, are not listed on the
Frankly, it appears that the U.S. government's current pesticide
program was designed primarily to protect something other than the
health and well being of the public.
Many pesticides now in use are simply not needed. For household pests,
the first line of defense should be mechanical control of flying pests
(screens, windows, nest removal, fly paper, and fly swatters). For
crawling insects (such as roaches), baits and traps work well and can
reduce the need for spraying whole areas.
To our way of thinking, William Pease asked the crucial question: since
non-toxic alternatives exist for controlling many pests, should the
government be licensing the use of toxic chemicals for controlling
those pests, knowing that some members of the public will needlessly --
and inevitably -- be harmed? When non-toxic alternatives exist, should
toxic alternatives receive a stamp of approval from the government? It
is an important ethical question.
 All information in this issue is from: Joel Grossman, "Dangers of
Household Pesticides," ENVIRONMENTAL HEALTH PERSPECTIVES, Vol. 103, No.
6 (June 1995), pgs. 550-554.
Descriptor terms: pesticides; household use statistics; labeling;
poisoning; active ingredients; inert ingredients; fifra; regulations;
regulation; epa inspector general; niehs; neurological damage;
neurotoxicity; immune system damage; immunotoxicity; children;