Ask Well
Everyone says that the DEET in
bug spray is awful, but my own research seems to suggest that it's well tested
and safe. Am I giving myself a little bit of cancer every time I use it?
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A DEET-containing bug spray might
smell unpleasant, but when used correctly, DEET's offensive odor might be its
most harmful effect, said Dr. Joseph Kennedy, a physician and medical
toxicologist at the University of Vermont Medical Center.
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Still, there's widespread concern
that DEET might be toxic or cause cancer, he said.
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Here is why people think DEET is
bad for human health, and what we know about its safety.
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Contrary to what many people may
think, DEET is not an insecticide, Dr. Kennedy said. It doesn't kill mosquitoes
and is not poisonous to them. Instead, it deters them, likely with its noxious
smell.
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"The whole point of smelling
unpleasant is you're not the only one that thinks that," Dr. Kennedy said.
"Insects do, too," he said. That includes other bugs like ticks,
fleas and biting flies.
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Another theory about how DEET
works is that it masks certain human emissions, like carbon dioxide, which
insects are normally attracted to, Dr. Kennedy said.
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Millions of people in the United
States use DEET-containing products every year, according to the Environmental
Protection Agency. Yet between 2007 and 2012, there were only about 2,800
reported health incidents involving the chemical, the agency said in its most
recent review.
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DEET has been used for about 80
years. If it was toxic or caused cancer, "it would have showed up a long
time ago," said Jeffrey Bloomquist, an insect toxicologist at the
University of Florida.
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Most incidents the E.P.A. noted
were minor, involving skin, eye or respiratory irritation like rashes, watery
eyes or wheezing.
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DEET-containing products are safe
when applied only to exposed skin and not sprayed directly onto the face or
broken skin, Dr. Bloomquist said.
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And don't use more than is
needed, Dr. Bloomquist said, especially with children. He recommended that
young children or infants use products with lower concentrations of DEET (a 24
percent solution should be adequate). And he suggested spraying it onto their
clothing.
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If used improperly, such as if
someone swallows it or applies too much, DEET can cause severe health effects
like seizures, low blood pressure, uncoordinated movements or death, Dr.
Kennedy said. But those cases are rare - seizures, for example, occur only once
in every 100 million uses, according to the E P.A.
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Little quality research on the
relationship between DEET and cancer has been conducted in humans, Dr.
Bloomquist said. The Centers for Disease Control and Prevention has reported
that long-term exposure is not associated with an increase in tumors in rodents,
rats or dogs.
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DEET also hasn't been shown to
cause harm to pregnant women or their fetuses.
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In the 1980s and 1990s, a few
isolated reports of seizures and deaths linked to DEET sparked concern.
However, those people hadn't used DEET as directed.
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Between 1960 and.2020,
researchers have reported nine deaths related to DEET poisoning. Of those, four
had intentionally swallowed the chemical - and among them, son had also
ingested other substances, like alcohol or antidepressants, which could have
played a role in their deaths. The other cases included two young children and
a baby whose parents had applied DEET every night for weeks or months, and two
adults who had applied more DEET than necessary. It's unclear if the DEET or
something else - such as an underlying health condition - played a role.
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One major benefit of DEET is its
ability to protect against insects that may transmit potentially deadly
illnesses like dengue, West Nile or Lyme disease.
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There are risks and benefits when
using any chemical, Dr. Kennedy said. But the toxic side effects of DEET are
far less common than what can occur with insect-borne illnesses, such as an
irregular heartbeat caused by Lyme disease or severe anemia with tick-borne
babesiosis, he said. "These truly life-altering diseases can be prevented
with just some basic precaution and application of a repellent."
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Isobel Whitcomb
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