Hello friends! Today I’m combining my environmental health science and nutrition backgrounds to chat about pesticides – specifically chlorpyrifos. You may have heard of chlorpyrifos. It’s been the news cycle a lot the past couple of years. Long story short, it was supposed to be banned, and then the ban got delayed, and now we’re still waiting for the ban to go through. But let’s back up – what is chlorpyrifos? Is it dangerous?
What is chlorpyrifos?

Chlorpyrifos is a broad-spectrum, chlorinated organophosphate pesticide (aka a chemical compound) commonly used for pest control on crops, animals, and in buildings. Chlorpyrifos was first introduced by DowDuPoint Chemical Company in 1965, and has a variety of registered food and non-food applications.
Chlorpyrifos is considered the most widely used insecticide in the United States.
Notably, chlorpyrifos is used as a pesticide on a variety of food crops, including many fruits, vegetables, grains, and nut trees.
It also has plenty of non-food uses, such as application to golf course turf, industrial sites, greenhouse production, farms, woods, and is often used in residential pest-control (it’s common in roach and ant bait products). It’s also been used as a public health-based application for mosquito-controls (most often in situations where the benefits of broad application outweigh the risks).
Is Chlopyrifos Dangerous?

Yes, chlorpyrifos can be harmful to human health. How exactly? Bare with me through some long scientific lingo and we’ll get to the facts soon, I promise.
Chlorpyrifos is classified as an organophosphate pesticide. Organophosphates inactivate the enzyme cholinesterase, which is responsible for deactivation of the nerve signaling protein acetylcholine, which leads to a buildup of acetylcholine, which over time causes overactivation of nerve targets, including those of the heart, brain, and digestive system, among others.
Overstimulation of these nerve targets is associated with nausea, dizziness, confusion, loss of muscle control, and death. It’s similar in chemical structure as some of the nerve agents used in WWII. It is considered a neurotoxicant.
Within the past decade, concern has risen about adverse health outcomes associated with chlorpyrifos from not only shorter, higher levels of exposure, but also longer-term lower levels of exposure.
In the early 2000s, scientific evidence began to suggest a link between chlorpyrifos use and a variety of adverse developmental outcomes. Perhaps most famously, researchers from th Child Columbia Center for Children’s Environmental Health (CCCEH) at Columbia Mailman School of Public Health (HUGE shout out to the alma matar!) found prenatal exposure (from residential environments – ie, spraying for bugs and pests) to chlorpyrifos causes structural changes in brain development.
The researchers at Mailman continued to study the chemical at levels of what wound be considered typical to high exposure, and found that prenatal exposure to chlorpyrifos is associated with deficits in working memory and lower IQ at age 7. Yes, that’s right. This chemical can have long-term cognitive impacts.
CCEH scientists have also shown that exposure to chlorpyrifos is also linked to lower psychomotor developmental index scores, and lower mental development index scores in children, and their research suggests boys may be more vulnerable than girls.
So, if this stuff is so bad for all of us, how is it still in use?

What a great question! I actually wrote a whole paper on the legality of chlorpyrifos in the United States, and holy cow, did that give me a headache. There have been multiple reviews, and re-assessments surrounding the ‘safety’ of chlorpyrifos.
Basically, there is science and wide-spread support to ban the use chlorpyrifos, however, due to changing administrations and very powerful (aka wealthy) chemical companies casting doubt on the science, the entire ban process has been extremely drawn out.
If you want a full timeline, check out the EPA’s page on this topic.
Otherwise, a very long story short, after evidence started accumulating about the dangers of chlorpyrifos, advocacy groups used the scientific data to pressure the EPA to regulate the use of chlorpyrifos. This eventually leading to the 2016 EPA ruling to revoke the allowed use of the chemical completely.
In fact, in 2016, the EPA ruled that there was no safe level of chlorpyrifos exposure for humans.
At some point, under the Obama administration, the evidence eventually brought the EPA to make the decision to ban the chemical. However, the EPA under Trump administration decided the evidence – the exact evidence the agency had used to justify the ban originally – was somehow no longer sufficient, and decided to delay the ban.
On August 9, 2018, the US 9th Circuit Court of Appeals ruled that chlorpyrifos must be banned within 60 days. However, the next month, the Department of Justice requested a rehearing before an en banc panel of the court’s judges, which was eventually granted on February 6, 2019, vacating the ruling of the previous year. After some more trials, the court ordered the EPA to make a final decision on the petition within 90 days.
I was honestly confused by the banning entire process; there seems to be a lot of back and fourth about the agency’s desire to ban or not ban the chemical. From what I could tell, as of this July, the pesticide is still in use, and the EPA is still undergoing “ongoing registration review” the science, trying to weigh whether or not the ban is warranted.
In case you’re wondering where the rest of the world sits, the Europoean Food Safety Authority has ruled there is no safe limit for human exposure chlorpyrifos, and Canada is in the process of reviewing a potential total ban.
What can I do to decrease my exposure to chlorpyrifos?

Unfortunately, it’s pretty difficult to completely avoid being exposed to chlorpyrifos. But, you can reduce your exposure by washing your produce. Yes, despite some articles I’ve seen about how it’s not important, do not skip washing your produce.
Eating organic produce has also been shown to reduce exposure to chlorpyrifos.
Also, throw away pest control products that contain Dursban (including brands like Tres Pasitos, Tempo, or Tiza China. If you have pest issues, consider sealing any cracks in your home, sprinkling boric acid in problem areas, and/or using sticky traps instead (the inner vegan in me wants to say catch and release them all – but the realist in me says: if that’s not your jam, follow the above mentioned advice).
And wash your hands often. Whether you’ve been handling produce or cleaning products or touching random poles on the subway, washing your hands is never a bad idea when striving to reduce exposure to chemicals or pathogens.
And, if you’re feeling like making some changes, reach out to your Congressperson about this issue. EarthJustice has a convenient form to help you reach yours and express concern over this particular topic.
Take home:
Yes, chlorpyrifos, which is the most commonly used insecticide in the United States, is dangerous. At high levels, it can cause coma, seizure, and death. At lower levels, it can cause neurodevelopmental delays and lower IQs in children.
Wash your produce and stop using pest control products that contain chlorpyrifos. And hit up your Congressperson to let them know you support a total chlorpyrifos ban in the United States!
Clearly, this is an issue I’m very interested in and passionate about. If you have questions/comments/concerns, thoughts, as always, drop me a comment down below, and/or reach out on Instagram, Twitter, or YouTube!
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