Published on July 26th, 2010 | by Steve Savage1
Lawsuit Against EPA Could Have Major Downside
Last week the NRDC (National Resource Defense Council) and PAN (Pesticide Action Network) sued the EPA demanding that it ban a particular insecticide called Chlorpyrifos. I have written to some of my NRDC contacts to ask: “why chlorpyrifos?”
Is Chlorpyrifos As Scary As They Say?
Although you would never know it from reading the uncritical news accounts of this suit, Chlorpyrifos is not quite the scary chemical that it is portrayed to be. It is the most widely used of an old class of pesticides called “Organophosphates,” but unlike some of those materials, this chemical is not all that toxic to mammals. It is almost exactly as toxic, gram-for-gram, as ibuprofen – the active ingredient if the popular, over-the-counter pain reliever, Advil®. It is many times less toxic than familiar natural chemicals like caffeine or capsaicin (e.g. in hot peppers). It is ~50% less toxic than certain copper-based fungicides that are approved for Organic production, and it is also used at lower rates than those materials. This is hardly a profile of a super high-risk chemical.
A Very Important Use of Chlorpyrifos
The bigger reason to question the wisdom of a ban comes from looking at how chlorpyrifos is actually used. At least for the area of major use, California, this is all publicly available information (see the CALPIP database).
It turns out that fully 38% of the total California use of chlorpyrifos is on tree nuts (Almonds, Walnuts, Pecans). In those crops it is used for the control of a caterpillar pest called the Navel Orange Worm. That particular pest not only causes damage on developing nuts, it carries with it a fungus called Aspergillus flavus which has the nasty habit of making an extremely toxic substance called Aflatoxin – one of the most potent toxins and carcinogens known. In the developing world this fungus and toxin are responsible for millions of liver cancer deaths every year through grain contamination. Our domestic nut industry does a fantastic job of protecting we consumers from this terrible toxin. Chlorpyrifos is an important tool to provide that protection. I don’t know about you, but I’d rather have a little Advil-level toxin on the outside of a nut shell than aflatoxin inside it!
Other Low Exposure Uses
Another 26% of CA chlorpyrifos use is on forage crops (mainly alfalfa) or fiber crops (cotton) that are not for human food. Another 14% of the chlorpyrifos is used on crops with low consumer exposure. This includes crops that are extensively washed during packing and peeled before eating (e.g. citrus); crops that develop underground away from the spray (onions, sugarbeets…); or crops which go through a fermentation step like wine grapes.
The remaining 22% of chlorpyrifos use is spread rather thinly across a wide variety of crops. In many cases, it is used in an occasional “rescue mode” to deal with occasional pest outbreaks. This allows even softer alternatives to be used for most of the season.
Does the NRDC/PAN Demand Make Sense?
There really does not seem to be any strong reason for EPA to consider an across-the-board ban on this product. Chlorpyrifos use is already down 60% from its peak in the ’90s, and most of the OPs have already been withdrawn or are only sparingly used. The linkage to ADHD that many news sources report is not at all confirmed at this point, and certainly not specific to chlorpyrifos (as many careless reporters have written).
A Parting Question
We have seen some big gaps in regulatory oversight recently (Financial markets, Oil extraction…), but frankly, the EPA has been doing its job quite well with regard to regulating this and related chemicals. I’d be interested in how NRDC and PAN suggest that nut growers maintain an aflatoxin-free crop if their lawsuit is successful? Perhaps they could sue the worms?
(Full disclosure: I have worked in the agricultural technology sector for over 30 years including chemicals. None of my clients happen to be manufacturers of chlorpyrifos, and no one is paying me to write about this or any other topic)
Navel Orange Worm image from UCANR.Org