Do We Have the Safety Test for Chemicals Wrong?


Imidacloprid, via WikiCommons

Imidacloprid, via WikiCommons

Humans are sometimes ridiculously anthropocentric. An example would be the test for whether a chemical is safe.1 The focus, obviously, is on hazards to humans. Is it safe for humans? Not safe for the environment. Not safe for, say, honeybees. Tests focus on whether a chemical causes cancer or disorders in people. Not disruption of the environment.

That’s kind of short-sighted. Take neonicotinoids, the class of chemicals that are now the most widely used pesticides in the world. They are used to protect plants grown for food, for energy, and for aesthetics. They work because they are toxic to all insects — the majority of the biome on Earth and by an order of magnitude the most diverse group of animals. But they’re far less toxic to non-insects, like birds and mammals, and thus are approved by the EPA for use on crops grown for human consumption.2

Dragonflies eat more insects that insecticides will ever kill but neonicotinoids kill dragonflies, too. Honeybees are critical to pollination of our crops, not to mention honey, but neonicontinoids kill honeybees as effectively as they kill cotton boll weevils and other insect pests. Neonicotinoids appear to impact bees’ ability to forage, learn and remember navigation routes to and from food sources. Sublethal neonicotinoid exposure is also implicated in colony collapse disorder.

It gets more complicated when you look at secondary effects. A lot of birds are insectivores: swallows, flycatchers, many warblers, swifts. If humans obliterate insects or even most insects over large areas, they obliterate the avifauna that depend on those birds.

By focusing almost exclusively on safety in humans, WC thinks the chemical safety laws are asking the wrong question. European Union laws are more sensible: the three main neonicotinoid insecticides (clothianidin, imidacloprid and thiamethoxam) are banned in the E.U. The E.U. evaluate hazards to the environment, not just to humans.

The problem is much larger than a single class of insecticide. The problem is that we are not asking the right questions.


  1. Never mind that the overwhelming majority of chemicals we use are never tested for safety. That would be the subject for a different blog post. 
  2. Not safe, mind you; rather less toxic. Like mustard gas is less toxic than nerve gas.