ANNAPOLIS — A locally used pesticide has come under state scrutiny for the second straight year.
Maryland lawmakers are again considering a state ban on chlorpyrifos, a pesticide used on fruit trees, vegetables, soybeans and row crops to control pests, for its potentially negative health effects on children and women of child-bearing age. The proposed ban has caused concern for farmers, however, who rely on the class of pesticides to protect their livelihoods from bugs.
“Chlorpyrifos is a powerful nurodevelopmental toxicant. Full stop,” said Devon Payne-Sturges, a former U.S. Environmental Protection Agency employee who managed the portfolio of research done to evaluate child and prenatal exposure to chlorpyrifos during her tenure at the agency.
Payne-Sturges is an assistant professor at the University of Maryland School of Public Health, and she testified in support of a statewide ban on the pesticide this past week in front of the House Environment and Transportation Committee. Based on her reading of the EPA’s 2016 Revised Human Health Risk Assessment, chlorpyrifos are unsafe for children ages 1 and 2 and women of child-bearing age, and there are no safe levels in drinking water.
EPA sets people’s acceptable exposures to pesticides as a “tolerance,” which is the maximum residue of the chemical on food.
Those who support the bill often spoke of there being no reasonable “tolerance” for chlorpyrifos. Farmers, trade organizations and the agri-chemical company Dow-DuPont instead asked that the state not intervene in federal pesticide labeling issue.
One of those farmers is Robert Black, who owns Catoctin Mountain Orchard near Thurmont, though he did not attend the House hearing.
Black uses chlorpyrifos in the winter on dormant trees before there is any fruit in his orchard. He is seeking out one specific bug: The peach tree borer, which overwinters in the bark of his fruit trees and, come spring, will eat its way inside and kill it.
“We use it once and we’re done,” Black said.
If he cannot use chlorpyrifos, then Black will have to consider other pesticides already on the market. He doesn’t like his options.
Black would have to use an estimated fourfold increase in neonicotinoids — which is less toxic to birds and mammals than chlorpyrifos but harmful to pollinators — or consider switching to pyrethrins. He’d rather not have to use the latter, which kills bugs indiscriminately and will likely kill the bugs that manage other pests naturally.
There is also the impending threat of the invasive spotted lanternfly migrating into Maryland from Pennsylvania. The destructive pest lays egg masses on smooth surfaces, such as tree trunks, which chlorpyrifos would also kill, Black said.
“If they keep taking our guns away and giving us rubber bands, how are we going to defend ourselves?” Black said, referring to chlorpyrifos as a metaphorical gun.
Not all farmers feel that chlorpyrifos need to stay on the market, though. Cleo Braver, a former environmental lawyer and current farmer of Nottingham Farm, delivered a letter signed by more than 40 farms in the state opposing chlorpyrifos and supporting existing alternative products to stop pests, including the peach tree borer.
She pushed back on the idea that farmers should reach for the “most effective” product first, rather than the “least toxic,” she said. Braver and the farmers signed on to her letter use products such as neem oil, BT, kaolin clay and cedar chips to control pests.
“Yes, it requires diligence, but it’s worth it to protect our community,” Braver said.
While chlorpyrifos have been in use since 1965, its makers voluntarily entered into an agreement with the EPA in 2000 to remove its household use. The pesticide is still used in agriculture and on turf grass — such as on golf courses — to control pests.
In high doses, it can overstimulate the nervous system, causing nausea, dizziness and confusion, according to the EPA. There is also a growing body of evidence that it can have negative health effects on children.
According to the EPA’s 2014 Revised Human Health Risk Assessment, “In spite of considerable differences in study design, upon review of the published literature a pattern of neurodevelopment adverse outcomes emerges.”
In 2017, the EPA denied a petition filed a decade earlier to revoke all tolerances for chlorpyrifos in food and its application labels. The denial resulted in a lawsuit, which the U.S. Court of Appeals for the 9th Circuit ruled in August 2018 the EPA must revoke all tolerances and cancel all registrations for chlorpyrifos within 60 days. The case is still being litigated.
The Maryland Department of Agriculture has taken no stance on the proposed ban.
“I understand no one wants to cause panic, no one wants to over reach, but as a scientist having been at EPA, as time marches on, the evidence gets stronger,” Payne-Sturges said.