A Michigan chemist invented chlorpyrifos more than 15 years after World War II, but environmental groups have succeeded in linking the insecticide to Nazi Germany nerve gases.

Restating an often-made claim, Earthjustice said in a press release last week that “organophosphates like chlorpyrifos” were “developed by the Nazis during World War II” and “repurposed for agricultural use.”

Chemist Josh Bloom of the American Council on Science and Health said it’s a fair statement to say chlorpyrifos is in the same class of chemicals as nerve gases such as sarin.

It’s also fair to lump sodium chloride (salt) with poisonous sodium cyanide, or a butter knife and a javelin, he said. “They’re both sort of sharp and made out of metal,” he said.

“If the Nazis had used chlorpyrifos, no one would have died.”

No link

Earthjustice issued the statement reacting to the 8th U.S. Circuit Court of Appeals decision to overturn the Environmental Protection Agency’s ban on using chlorpyrifos on food crops.

The ruling was the latest in a long battle over the insecticide. Environmental groups have repeatedly suggested the chemical has strong ties to Nazi Germany.

Nerve gases and organophosphate pesticides, such as chlorpyrifos, do disrupt the nervous system in the same way, according to the Centers for Disease Control and Prevention.

German chemist Gerhard Schrader was trying to develop a pesticide when he accidentally invented in 1936 the nerve gas tabun, the forerunner of the more potent sarin.

Earthjustice attorney Patti Goldman said in an email that organophosphates on the market are from the same class of chemicals as nerve agents such as sarin. “Organophosphates should be banned,” she said.

Washington State University chemistry professor Allan Felsot said there’s no reason to associate pesticides such as chlorpyrifos with nerve gases developed in Germany in the 1930s and ‘40s.

Chlorpyrifos and nerve gases have different purposes, health effects, histories and chemistries, he said.

“It’s a real misunderstanding or lack of knowledge about chemistry,” Felsot said. “It’s two separate lines of synthesis investigations.”

Claim spread

Media reports have picked up and even expanded on the claim. The Los Angeles Times in 2018 called chlorpyrifos, “a pesticide initially developed as a nerve gas during World War II.”

The New York Times editorialized in 2019 that it wasn’t “entirely surprising” chlorpyrifos causes health problems. “The chemical was originally developed by Nazis during World War II for use as a nerve gas.”

New York Times columnist Nicholas Kristof proposed renaming chlorpyrifos “Dow Chemical Company’s Nerve Gas” and facetiously suggested Dow would use sarin if it learned it was more effective than chlorpyrifos.

Organophosphorus pesticides and nerve gases are fundamentally different, Felsot said.

“Nerve gases are effective at penetrating the skin. That’s what makes those things so dangerous,” he said. “That’s not true for chlorpyrifos.

“The concern with chlorpyrifos is chronic exposure over a long period of time,” Felsot said. “With sarin there is no exposure for long periods of time because it’s going to kill you right away.”

Bloom said environmental groups use scare tactics that exploit a lack of knowledge about chemistry. “I think they don’t know what they’re talking about, but they know what they’re doing,” he said.

“Chemistry is a difficult subject and most people avoid it,” Bloom said. “If you don’t study chemistry, there’s no way you can tell a false claim from a true claim.”

Schrader testified at the Nuremberg trials that he invented tabun as an insecticide, but his employer turned it into a war gas. Germany manufactured nerve gas, but did not use it, on battlefields or gas chambers.

After the war, Schrader declined an invitation to help the British develop chemical weapons. “I am glad to be fully engaged again in the field of plant protection,” he wrote British intelligence officers.

In 1951, chemist Raymond Rigterink, a Michigan native and Purdue University graduate, was recruited for a Dow Chemical team synthesizing organophosphates, according to a 2000 article in The Midland (Mich.) Chemist.

Dow applied for a patent for chlorpyrifos in 1962 and credited Rigterink as the inventor, according to U.S. Patent Office records.

According to the patent, Rigterink discovered compounds useful to control mites, beetles, ticks, worms, aphids, flies, roaches, snails, cattle grubs, screw worms and other pests, without damaging plants.

Rigterink was credited with 50 patents during his 41-year career with Dow, according to The Midland Chemist. (Dow no longer registers any chlorpyrifos products.)

Rigterink died in 2009 at the age of 92. He was an avid gardner and charter member of a Presbyterian church, according to an obituary in the Midland Daily News.

Court overturns EPA’s ban on chlorpyrifos