Toxic impacts of chlorpyrifos pesticides

From ToxicLeaks

History and development[edit | edit source]

The use of chlorpyrifos in the United States spans a 50-year trajectory, with the research and legal battles over its use continuing for about half that long. The organophosphate insecticide was placed under patent by Dow Chemical in 1965 and brought to market in 1972 as the Lorsban® insecticide, although it is sold under other names including Dursban, Bolton Insecticide and Nufus. It was used in the United States for both residential and agricultural pest control until 2000, when the U.S. Environmental Protection Agency banned its use in the former with few exceptions. That same year, chlorpyrifos application was prohibited on all tomatoes, and limited for apple orchards and vineyard operations.

Limitations for use on citrus and nut trees were introduced in 2002, and by 2007 a legal challenge – one of many since the early 1990s – forced the EPA to consider a total ban. That process was delayed until, despite the EPA’s own decision about human health risks caused by chlorpyrifos, President Donald Trump’s administration and EPA appointee Scott Pruitt decided in March 2017 to keep chlorpyrifos products available as an agricultural pesticide to American growers.

The product – a white crystal with a musky odor – is most widely used on corn, but is commonly applied to other crops as well. It is also available for use on golf courses and other nonproducing land, for treating utility poles and fences, and may be used in some products to control termites, mosquitoes and cockroaches.

Health impacts discovered[edit | edit source]

Because it is a neurotoxin, chlorpyrifos blocks an enzyme that communicates signals through the nervous system of humans and wildlife. It can be harmful if it is absorbed through human skin, ingested and in many exposures, inhaled by those living or working near agricultural sites where the product is used.

Short-term symptoms include drooling or mild nausea, all the way up to seizures, respiratory distress and paralysis in severe toxicity cases. Beginning in the 1990s, however, the consequences of long-term exposures began to get the attention of biologists, researchers, and public health and environmental advocates. Some of the first evidence of chronic exposure showed effects on the sensory system. Other research found health risks including low birthweights and childhood tremors after prenatal exposure.

Evidence of the effects on babies and children mounted, since their developing metabolic systems handle the neurotoxin exposure in more nuanced – and alarming – ways. Prenatal exposure was linked to intellectual development, including lower IQs, learning disabilities and autism spectrum disorders. A 2012 study linked chlorpyrifos exposure to structural changes in the developing brain.

In a landmark study widely disputed by DowAgro and industry activists such as CropLife America, the Columbia Center for Children’s Environmental Health followed 725 African-American and Dominican mothers and children in New York City who used the product to kill cockroaches and other insect pests.

Ninety-nine percent of the air sampled from the subjects’ apartments tested positive for chlorpyrifos, as did 70 percent of the blood samples taken from the mothers and their children. At the same time that Columbia was completing their work, the EPA banned indoor use – leaving what they say was a clear before-and-after comparison of chlorpyrifos concentration levels and the correlation with health risks.

EPA bans and rulings[edit | edit source]

The EPA indoor ban, and later agricultural restrictions, came after years of legal challenges dating back to 1992. In one of the earliest cases, Dow stonewalled attorneys who requested any documentation of adverse effects tied to the pesticide. A judge cleared the way, and Dow was forced to release evidence of 220 such cases that had never been reported to the EPA. By 1995, EPA had fined the company nearly $900,000 for falsely advertising its products were safe; they paid another $2 million in 2003 in a case brought by the attorney general’s office in New York – but continued selling a product that research scientists, government officials, health and environment advocates and the public knew was unsafe.

The chemical has also been found in drinking water, and by EPA’s own 2016 assessment creates a food residue risk that is shockingly high when compared with the agency’s acceptable limits. Although the EPA had never responded in a timely manner to a 2007 lawsuit filed by Earthjustice, on behalf of Pesticide Action Network (PAN) and Natural Resources Defense Council (NRDC), by late 2014 the agency accepted the scientific findings on chlorpyrifos health risks and proposed to end its U.S. agricultural use.

Trump era reversal[edit | edit source]

The EPA had until the end of March 2017 to make its final determination. Under newly elected President Donald Trump and EPA appointee Scott Pruitt – both known to be hostile to environmental priorities and regulatory frameworks unfriendly to corporate interests – the decision to continue chlorpyrifos use was entered. “By reversing the previous Administration’s steps to ban one of the most widely used pesticides in the world, we are returning to using sound science in decision-making – rather than predetermined results,” Pruitt said, echoing almost verbatim the language of the corporate lobbyist.

Countering the chlorpyrifos ruling[edit | edit source]

On April 5, Earthjustice filed a motion requesting the courts to, among other things, force EPA to issue within 60 days, a notice of intent to cancel all chlorpyrifos uses. The filing is based on the contention that the court has the authority to insist that EPA act on its own findings – the trajectory of which is recapped in the brief – and cannot wait an additional five years as part of a routine regulatory review.

Additionally, the State of California, home to a key growing region and 20 percent of the chlorpyrifos used in the U.S., is exploring options for banning its use at the state level. State air monitoring in its farm communities has found chlorpyrifos levels that exceed EPA safety targets by three to 44 times. A ban would be a powerful market signal, since the state grows more than a third of U.S. vegetables and two-thirds of U.S. fruits and nuts. Environmentalists in Hawaii also are pushing for a state-level ban.