Two Examples of Safety Progress: Automobile Travel and Agricultural Pest Control

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I remember the first time I wore a seatbelt.  It was 1964 and I was nine.  My dad had them installed in our Chevrolet Bel Air Station Wagon.
The lack of seat belts was only one of many safety deficiencies of that vehicle! Obviously there have been vast improvements in the safety of car travel since that time.  No one would be surprised to read that the US rate of fatalities per million miles of vehicle travel has been dropping every year since 1920 and is now down to the range of 2 people per million miles driven.
Vehicle travel is still a leading cause of death, but we have made great strides in the relative safety of this important activity and everyone knows about it.

A Less Appreciated Example of Safety Progress

The safety of pest control in agriculture has also improved dramatically over the same time period, but this is something that most people don’t know about or wouldn’t be likely to believe.  I think there are four main reasons for this difference in the perception of safety progress:

1. Very few people have any direct or even indirect involvement in farming that would allow them to experience the changes
2. Few people understand the critical difference between “hazard” and “risk”
3. The way that the EPA regulates pesticide risk does not allow for relative safety claims
4. There are numerous groups in society with a vested economic interest in having people be frightened about pesticides and other technologies

The Status Of Pest Control When I Was Riding In The ’63 Bel Air

When I was nine and first “buckling up for safety,” farmers didn’t have particularly good tools for controlling pests, and the ones they had were often nasty.  They had products based on heavy metals (tin, copper, even mercury).  They had products based on arsenic.  They had products based on sulfur or lime sulfur.  They had some synthetic chemicals including DDT and some of the early, and very toxic Organophosphates.  There was no Environmental Protection Agency and only an emerging understanding of the environmental, worker, and consumer safety issues.

What Changed?

All of this began to change in the late sixties and there has been tremendous progress since that time.  I’ve been directly involved in this field since 1977 and I have seen significant changes of at least eight types (listed in declining order based on my best guess of their relative contribution to safety progress):
1. Development of new pesticide products with very low intrinsic toxicity or environmental impact
2. De-registration or discontinuation of the pesticides with serious risk issues for the environment or human health

3. EPA regulation of pesticide use pattern restrictions (minimum re-entry intervals, rate limitations – total and per use, protective equipment requirements, minimum pre-harvest intervals) which limit worker exposure and consumer residue exposure
4. Integrated Pest Management (IPM) approaches (scouting, economic thresholds for application,  trap crops, crop rotation, attention to preservation of natural enemies…)
5. Precision Application (seed treatments vs furrow drenches, electrostatic sprayers, drift control technologies…)
6. Advances in genetic pest resistance via traditional breeding, Marker Enhanced Breeding, or Biotechnology
7. Progress in non-pesticidal control methods (pheromone confusion, microclimate management, protected culture…)
8. Biological controls (a very cool approach and one I worked on for many years, but honestly a relatively small part of the solution)

Conclusion

I’ll make this personal.  I’m really glad that my grand daughter will do all her automobile travel in vehicles that are far safer than what I survived (we also had no infant car seats).  I’m equally glad that she has a food supply that is cheaper, safer, more environmentally sustainable, and vastly more diverse than what was available to my family when I was a child.  I just wish that more people understood the later change.

Bel Air poster image from hugo90

Other images from Steve Savage

What Are Your Favorite Toxins?

(originally posted on Sustainablog, 1/4/11)

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From what I read on various blogs and their comment streams, it is obvious that there are a lot of people who are very concerned about toxins in their food and water. Many say they want to live in a “toxin-free world.”  Although I would be the first to say that there are some toxins that are worth worrying about, my concern is that there are a lot of people suffering from excessive angst about toxic substances because they don’t know two important facts:

Fact 1. Our world is actually full of toxins – mostly of natural origin.

Some of the natural toxins are really scary, but some of them are delicious or useful.  Some of my favorite natural toxins include the caffeine in my morning coffee, the capsaicin in the spicy Mexican and Thai dishes I love, and the tomatine in the tomatoes I eat.  These are all natural chemicals that are actually toxic – even quite a bit more toxic than a typical pesticide today.  So why is it OK to enjoy these and many other foods that contain toxic chemicals?  That is where the second fact comes in.

Fact 2. There is an important difference between hazardand risk.

The reason that so many people are troubled by the idea of toxins is that our educational system fails to teach us what we need to understand which toxins are really worth concern and which are not.  We don’t tend to learn the difference between hazard and risk.

To illustrate this, consider electricity.  Electricity is an extremely useful thing, but it is also extremely hazardous.  People can and do die from electrocution.  But although electricity will always be hazardous, we take important steps to make sure we are not exposed directly to the electricity and thus the risk is low. Our appliances can be safe even though they are powered by a very hazardous thing.

What About The Toxins in Our Food?

So even though I consume lots of plant-based chemicals that are actually toxic (a hazard), the quantities are low enough that the risk is too low to worry about.   For instance, I calculated that for me (at 175 lbs), it would take 169 cups of strong coffee (~90 milligrams of caffeine in each) to get enough to be lethal (a dose of 192 mg/kg could be toxic to mammals). With a “safety margin” of 169, it is reasonable that few people worry when they consume this toxin every day.

What about the sort of toxins that people do worry about - like pesticide residues on foods?  Each year a group in the USDA buys produce from stores around the US and tests it for pesticide residues.  You can get the data on  line.  The Environmental Working Group uses this data each year to come up with their “dirty dozen” list which they successfully use to scare consumers away from buying as much fresh produce.  That is unfortunate because what the USDA data actually shows is that the pesticides (which are almost all much less toxic than caffeine) are also present at such low levels as to be negligible.

To demonstrate this, I took the data for strawberries in 2008 and calculated the safety margins for every single pesticide residue that was detected (assuming 1/2 lb of strawberries consumed by me at 175 lbs).  The smallest safety margin was 5,895 – thirty five times less risky than a cup of Joe.  The vast majority of residues on the strawberries had safety margins of from a million to a billion (see chart below).  Not much to be scared about here!

But What About the Long Term?

“But,” many people will say, “what about long-term exposure to low doses?”  This is obviously something much more difficult to study.  The best approach has been to test the medium-term (1-2 year) effects of a fairly high, but non-lethal dose.  Practically speaking, this is the only way to get an answer within any reasonable time and budget constraints (still costing many millions of dollars).   These tests have identified carcinogens and chronically toxic materials among both natural and synthetic chemicals.   Many such tests have been conducted with caffeine and the consensus result is that, no, it is not a carcinogen or chronic toxin of concern at the levels we consume.  We have learned fairly well how to screen for compounds with chronic effects and such tests are required for all pesticides.

The Professional Doubters

The Environmental Working Group ignores this data and maintains that “we just never know” whether there might be low level effects.  If they are right, then we are mainly at risk from natural toxins.  We consume them at far high rates, and in most cases, they have never even been studied for chronic effects.  If we accept the view of the EWG, there really isn’t much of anything that we could eat without fear of some long-term downside.  That sort of view is good for EWG’s fundraising efforts.  It is not a good thing for encouraging the consumption of healthy foods.

I don’t know about you, but I would rather just enjoy my food – toxins and all.

Strawberry and Coffee image from smittenkittenorig

Safety Margin Graph by Steve Savage using USDA AMS PDP data

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