10 Times as Much of This Toxic Pesticide Could End Up on Your Tomatoes
and Celery Under a New EPA Proposal
"Against the guidance of scientific advisory panels, the EPA is relying on
industry-backed tests to relax regulations on acephate, which has been
linked to neurodevelopmental disorders. “It’s exactly what we recommended
against,” one panelist said.
by Sharon Lerner
April 24
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When you bite into a piece of celery, there’s a fair chance that it will be
coated with a thin film of a toxic pesticide called acephate.
The bug killer — also used on tomatoes, cranberries, Brussels sprouts and
other fruits and vegetables — belongs to a class of compounds linked to
autism, hyperactivity and reduced scores on intelligence tests in children.
But rather than banning the pesticide, as the European Union did more than
20 years ago, the U.S. Environmental Protection Agency recently proposed
easing restrictions on acephate.
The federal agency’s assessment lays out a plan that would allow 10 times
more acephate on food than is acceptable under the current limits. The
proposal was based in large part on the results of a new battery of tests that
are performed on disembodied cells rather than whole lab animals. After
exposing groups of cells to the pesticide, the agency found “little to no
evidence” that acephate and a chemical created when it breaks down in the
body harm the developing brain, according to an August 2023 EPA
document.
The EPA is moving ahead with the proposal despite multiple studies linking
acephate to developmental problems in children and lab rats, and despite
warnings from several scientific groups against using the new tests on cells
to relax regulations, interviews and records reviewed by ProPublica show.
To create the new tests designed to measure the impact of chemicals on the
growing brain, the EPA worked with the Organization for Economic
Cooperation and Development, which comprises some of the world’s
wealthiest democratic countries and conducts research on economic, social
and scientific issues. The OECD has warned against using the tests to
conclude a chemical does not interfere with the brain’s development.
A scientific advisory panel the EPA consulted found that, because of major
limitations, the tests “may not be representative of many processes and
mechanisms that could” harm the developing nervous system. California
pesticide regulators have argued that the new tests are not yet reliable
enough to discount results of the older animal tests. And the Children’s
Health Protection Advisory Committee, a second group of advisers
handpicked by the EPA, also warned against using results of the nonanimal
tests to dismiss concerns.
“It’s exactly what we recommended against,” Veena Singla, a member of the
children’s committee who also teaches at Columbia University, said of the
EPA’s acephate proposal. “Children’s development is exquisitely sensitive to
toxicants. … It’s disappointing they’re not following the science.”
The EPA’s proposal, which could be finalized later this year, marks one of the
first times the agency has recommended changing its legal safety threshold
largely based on nonanimal tests designed to measure a chemical’s impact
on the developing brain. And in March, the EPA released a draft assessment
of another pesticide in the same class, malathion, that also proposes
loosening restrictions based on similar tests.
The proposed relaxing of restrictions on both chemicals comes even as the
Biden administration has been strengthening limits on several other
environmental contaminants, including some closely related pesticides.
In response to questions from ProPublica, the EPA acknowledged that it “will
need to continually build scientific confidence” in these new methods but
said that the introduction of the nonanimal tests to predict the danger
chemicals pose to the developing brain “has not been done in haste. Rather,
a methodical, step-wise approach has been implemented over the course of
more than a decade.”
The agency said its recent review of acephate included a thorough
examination of a variety of scientific studies and that, even with its proposed
changes, children and infants would still be protected.
The EPA expects to start accepting public comments on the acephate
proposal in the coming months before it makes a final decision. The agency
anticipates soliciting comments on malathion this summer.
Some environmental scientists strongly oppose loosening the restrictions on
both acephate and malathion, arguing that the new tests are not reliable
enough to capture all the hazards a chemical poses to the developing brain.
“It will put children at an increased risk of neurodevelopmental disorders like
autism and ADHD that we already know are linked to this class of chemicals,”
said Rashmi Joglekar, a toxicologist at the Program on Reproductive Health
and the Environment at the University of California, San Francisco.
Health and environmental scientists are concerned about more than the
direct impact of having potentially greater amounts of acephate and
malathion on celery and other produce. They also worry that using the new
tests as a basis for allowing more pesticides on crops will set a dangerous
precedent for other brain-harming chemicals.
“I think the companies see this as a new way over a 10- or 20-year period to
gradually lobby” the EPA “to allow higher levels of pesticides in food,” said
Charles Benbrook, an agricultural economist who has monitored pesticide
regulation for decades. “If they can convince regulators to not pay attention
to animal studies, they have a very good chance of raising the allowable
exposure levels.”
Industry Helped Fashion EPA’s Testing Strategy
Since its founding in 1970, the EPA has relied on studies of mice, rats, guinea
pigs and other species to set exposure limits for chemicals. The lab animals
serve as a proxy for humans. Scientists expose them to different doses of
substances and watch to see what levels cause cancer, reproductive
problems, irritation to the skin and eyes, or other conditions. Some tests look
specifically at chemicals’ effects on the offspring of rats exposed during
pregnancy, and some of those tests focus on the development of their brains
and nervous systems.
But over the past decade, chemical manufacturers and animal rights
advocates have argued for phasing out the tests on the grounds they are
impractical and inhumane. The animal experiments are also expensive, and
the pesticide industry, which by law shoulders the cost of testing its
products, is among the biggest proponents of the change.
The EPA has allowed the chemical industry and animal rights groups to help
fashion its testing strategy. Agency officials have co-authored articles and
held workshops on the use of the cell-based tests to regulate chemicals
alongside representatives of People for the Ethical Treatment of Animals as
well as Corteva Agriscience, BASF and Syngenta Crop Protection, companies
that make pesticides regulated by the EPA.
The EPA said its scientists have been working to develop the nonanimal tests
for decades with other government and scientific organizations, both
nationally and internationally.
“It is absurd to describe those scientific efforts as an apparent conflict of
interest,” the agency said in a statement.
The EPA’s Office of Pesticide Programs has previously come under fire for its
willingness to allow pesticides onto the market without required toxicity
testing. In 2018, as The Intercept reported, staff members held a party to
celebrate a milestone: The number of legally required tests the office had
waived for pesticide companies had reached 1,000. A science adviser to the
office at the time said the move spared companies more than $6 million in
expenses.
While phasing out animal experiments would save money and animal lives,
experiments involving collections of cells do not always accurately predict
how entire organisms will respond to exposure to a toxic chemical. The new
cell-based tests and computer techniques that are sometimes used with
them can be reliable predictors of straightforward effects like eye or skin
irritation. But they are not yet up to the task of modeling the complex, real-
world learning disorders that have been linked to acephate and malathion,
according to Jennifer Sass, a senior scientist at the Natural Resources
Defense Council, an environmental advocacy organization.
Credit: Photo illustration by Lauren Joseph/ProPublica. Source images by
Getty and the Environmental Protection Agency
The new tests can show whether a chemical can kill a brain cell. And they
can show if a chemical affects how a brain cell connects with other brain
cells, said Sass.
“But these tests can’t show that a kid is going to be able to sit through class
and not go to the principal’s office,” she said.
While the cell-based tests may point to certain harms, they are likely to miss
others, said Sass, who likens their use to fishing with a loose net. “You only
know what you caught — the big stuff,” she said. “You don’t know about all
the little stuff that got through.”
A 2023 study revealed the failure of the cell-based tests to detect certain
problems. In it, scientists exposed brain cells to 28 chemicals known to
interfere with the development of the nervous system. Although the tests
were specifically designed to assess whether chemicals harm growing
brains, they failed to clearly identify harm in one-third of the substances
known to cause these very problems. Instead of registering as harmful, the
test results on these established developmental neurotoxins were either
borderline or negative.
Because of these potential blind spots and other uncertainties associated
with the tests, the Organization for Economic Cooperation and Development
has advised against interpreting results of the nonanimal tests as evidence
that a chemical doesn’t damage the brain. Several scientific groups have
recommended that the EPA do the same.
A federal advisory panel of scientists assembled to advise the EPA on
pesticide-related issues published a 2020 report that identified numerous
limitations and gaps in the nonanimal studies, finding that they
“underestimated the complexity of nervous system development.”
In 2021, the Children’s Health Protection Advisory Committee, a group the
EPA created to provide advice on how to best protect children from
environmental threats, warned the agency that, “due to important
limitations,” the test results “cannot be used to rule-out a specific hazard.”
In comments to the EPA, California’s Department of Pesticide Regulation also
cautioned the agency against using the tests to conclude that a chemical
doesn’t cause specific harms. The California regulators emphasized that the
traditional battery of animal tests was still necessary to understand complex
outcomes like the effects on children’s developing brains.
“To abandon it at this time would be to abandon a critical support for health-
protective decisions,” they wrote.
EPA Accused of Double Standard
As much as 12 million pounds of acephate were used on soybeans, Brussels
sprouts and other crops in 2019, according to the most recent estimates
from the U.S. Geological Survey. The federal agency estimates that up to
30% of celery, 35% of lettuce and 20% of cauliflower and peppers were
grown with acephate. Malathion is used on crops such as strawberries,
blueberries and asparagus. (The U.S. Department of Agriculture prohibits the
use of most synthetic pesticides, including acephate and malathion, to grow
and process products certified by the agency as organic.)
Acephate and malathion belong to a class of chemicals called
organophosphates, which U.S. farmers have used for decades because they
efficiently kill aphids, fire ants and other pests. But what makes the
pesticides good bug killers — their ability to interfere with signals sent
between nerve cells — also makes them dangerous to people. For years,
there has been a scientific consensus that children are particularly vulnerable
to the harms of pesticides, a recognition that led the EPA to strengthen
restrictions on them. But with both acephate and malathion, the agency is
now proposing to remove that extra layer of protection.
The EPA effectively banned another organophosphate pesticide,
chlorpyrifos, in 2021, based in part on evidence linking it to ADHD, autism
and reduced IQ in children. (In response to a lawsuit brought by a company
that sells the pesticide and several agricultural groups, a court vacated the
ban in December, allowing the resumed use of chlorpyrifos on certain crops,
including cherries, strawberries and wheat.) While some health and
farmworker groups are petitioning the EPA to ban all organophosphate
pesticides, the agency is arguing that it can adequately protect children by
limiting the amount farmers can use.
Several studies suggest that, even at currently allowable levels, acephate
may already be causing learning disabilities in children exposed to it while in
the uterus or in their first years of life. In 2017, a team of University of
California, Berkeley researchers, partly funded by the EPA, found that
children of Californians who, while pregnant, lived within 1 kilometer of where
the pesticide was applied had lower IQ scores and worse verbal
comprehension on average than children of people who lived further away.
Two years later, a group of UCLA scientists reported that mothers who lived
near areas where acephate was used during their pregnancies had children
who were at an increased risk of autism with an intellectual disability.
The EPA considered this research when deciding to relax the limits on
acephate use but stated that flaws and inconsistencies made these
epidemiological studies “not compelling.” The agency also dismissed a rat
study submitted to the EPA in 2005 in which the pups of mother rats
exposed to higher levels of acephate were, on average, less likely to move
than the pups of mothers exposed to lower levels. The EPA told ProPublica
that “no conclusions could be drawn” from the experiment, citing the “high
variability of the data” it produced. But some scientists outside the agency
find that study a particularly worrisome indication of the pesticide’s potential
to harm children.
In its proposals to increase the allowable amount of both acephate and
malathion on food, the EPA also had to look past other potentially concerning
test results. Some of the cell-based tests of acephate showed borderline
results for interference with brain functions, while some of the tests of
malathion clearly indicated specific problems, including interference with the
connections between nerve cells and the growth of certain parts of nerve
cells. Several scientists interviewed by ProPublica said that such results
demand further investigation.
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Some scientists see a double standard in the agency accepting the imperfect
nonanimal tests while citing flaws in other research as reasons to dismiss it.
“They’re acknowledging limitations in epidemiology while at the same time
not acknowledging the even greater limitations of using a clump of cells in a
petri dish to try to model what’s happening in a really complex organism,”
said Nathan Donley, a scientist at the Center for Biological Diversity, an
environmental advocacy organization.
Asked about the criticism, an EPA spokesperson wrote in an email to
ProPublica that the agency “does not believe there was a double standard
applied.”"
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