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One truism (Dickeyism?) is that corporations – including Big-Ag outfits – absolutely hate to voluntarily take products off the market that are profitable. 

This is the story of Dow Chemical and DuPont and its decades old pesticide chlorpyrifos...although it could just as easily be applied to any Big Ag product manufacturer.  What's chlorpyrifos you ask?

The Environmental Protection Agency first registered chlorpyrifos in 1965 as a pesticide for use on row crops including corn and soybeans as well as fruit and nut trees, broccoli, cauliflower, cranberries and brussel sprouts.  It was also used heavily in non-agricultural applications like golf courses and it received registration as a mosquito adulticide. 

But sometimes even the most stringent EPA product registration review fails to uncover unwanted consequences. Or laws change.

It turns out that the the Food Quality Protection Act of 1996 signaled that chlorpyrifos had serious problems. The act required that EPA when setting pesticide tolerances to make a safety finding that a chemical can be used with “a reasonable certainty of no harm,”

EPA's review of chlorpyrifos required Dow and DuPont to address safety concerns as well as environment and health risks.  Dow and Dupont voluntarily entered a deal with EPA that eliminated most homeowner uses of chlorpyrifos and farmers could no longer use the chemical on tomatoes, faced restricted use on apples and lower residue levels on grapes.

That turned out to be just the tip of the iceberg.  In 2002 EPA required label changes on chlorpyrifos to insure environmental and worker safety.

And then in 2011 the hammer fell.  A preliminary health risk assement of  chlorpyrifos speculated the chemical may have negative neurological impacts on human children and babies.  Still Dow and DuPont defended chlorpyrifos.

Subsequent EPA health risk assessments in 2014 and 2016 of chlorpyrifos did nothing to calm fears that the chemical hurt kids. 

All those EPA risk assessments as well as a  petition filed by the Natural Resources Defense Council and Pesticide Action Network North America were enough for the Obama Administration to move to ban chlorpyrifos in part recognizing long term studies suggesting moderate exposure during pregnancy can lead to long-term brain damage on children.

But DuPont and Dow still wasn't ready to throw in the towel, opting to wage a messenging war insisting chlorpyrifos was safe.

And that messenging war paid dividends.  In 2017 the Trump EPA reversed the Obama administration plan to ban chlorpyrifos.

Enter the federal courts.  The Pesticide Action Network and the Natural Resources Defense Council filed against the EPA in an effort to force the agency to follow through on the Obama ban proposal.

Last April a federal appeals court gave EPA 90 days to ban chlorpyrifos.

Finally this February Corteva which was spun off a merger of Dow and Dupont last year – indicated it would end production of chlorpyrifos by the end of this year.

Corteva doesn't end production on health or environmental concerns but rather that the chemical isn't as profitible as it once was.  In fact Corteva goes so far as to say the product is safe

Corteva also says U-S demand for chlorpyrifos is less than 20% of what it was during its peak in the 1990s.


Corteva really had no choice but to claim chlorpyrifos is safe.  To do otherwise would open the company up to massive lawsuits.  And yes Corteva did see dwindling sales, not only in the U-S but also the European Union where chlopyrifos has been banned.

It also probablly gave Corteva some sleepless nights that three states have banned chlopyrifos – Hawaii, New York and most recently California.

The moral of the story is if you pound away hard enough and long enough at Big Ag's profitability in the name of health and environmental concerns behaviorial change is possible.

Since its first registration in 1965, chlorpyrifos has been reviewed several times by EPA for tolerance reassessment, reregistration, and most recently, as part of its ongoing registration review. The following timeline summarizes the work EPA has done to ensure that, as science and technology evolve, registered chlorpyrifos products remain safe for use.  

Corteva, spun off last year after a merger of Dow Chemical and Dupont, said declining sales drove its decision to end production and officials continue to believe chlorpyrifos is safe. 

The company’s move reflects a shift toward newer products in the $14.5 billion global agrichemicals industry amid increased regulatory restrictions on chlorpyrifos, which is applied to crops from corn to cauliflower. Environmental groups have pushed regulators to ban uses of the 55-year-old pesticide over concerns it harms people and wildlife. 

“We’ve made the difficult decision to stop our manufacturing of chlorpyrifos,” Susanne Wasson, president of Corteva’s crop protection business, told Reuters. 

In the U.S., Corteva’s biggest market for chlorpyrifos, demand is less than 20% of what it was during its peak in the 1990s, the company said. Industry sales were $350 million in 2005, down 45% from 1990, according to Corteva. 

By volume, estimated use dropped to under 5 million pounds in 2016 from about 13 million pounds in 1994, U.S. Geological Survey data show. 

Corteva, which sells chlorpyrifos under the Lorsban brand, faces competition from generic versions. Farmers seeking to fight insects have also turned to other chemicals, genetically engineered crops and seeds coated with pesticides. 

Demand for chlorpyrifos is expected to drop further amid regulatory restrictions, including an EU decision to ban uses of the pesticide, Corteva said. 

On Thursday, manufacturers must stop sales in California under an agreement with the state, which says chlorpyrifos is harmful. California farmers cannot possess or use chlorpyrifos products after Dec. 31. 

“Children and farm workers in California will no longer be exposed to this neurotoxic pesticide that can permanently impair the brain and nervous systems,” said Ken Cook, president of Environmental Working Group, an activist organization. 

The U.S. Environmental Protection Agency reversed a ban on chlorpyrifos use on farms under President Donald Trump, saying there was not enough evidence to link it to children’s health problems.

Corteva said it will continue to support chlorpyrifos in an EPA review. 

“We believe in the product,” Wasson said. 

Corteva previously agreed to sell chlorpyrifos assets in India and has assessed its portfolio to ensure it is the best owner of businesses. Sales in its crop protection unit dropped 3% to $6.26 billion in fiscal year 2019. 

About Dave Dickey

Dave Dickey

Dickey spent nearly 30 years at University of Illinois at Urbana-Champaign’s NPR member station WILL-AM 580 where he won a dozen Associated Press awards for his reporting. For 13 years, he directed Illinois Public Media’s agriculture programming. His weekly column for the Midwest Center covers agriculture and related issues including politics, government, environment and labor. His opinions are his own and do not reflect the Midwest Center for Investigative Reporting. Email him at