How Safe Substances Become Dangerous
The recent decision by the IARC to label the commonly used herbicide 2,4-D as “possibly carcinogenic to humans" is based on a mistaken application of toxicology. If substances like 2,4-D are made unavailable, American farmers will be forced to resort to other methods to control weeds – none of them as safe or efficient.
Legitimate objections have been raised about the independence and integrity of the commentaries that Henry Miller has written for Project Syndicate and other outlets, in particular that Monsanto, rather than Miller, drafted some of them. Readers should be aware of this potential conflict of interest, which, had it been known at the time Miller’s commentaries were accepted, would have constituted grounds for rejecting them.
PALO ALTO – Since the development of the science of toxicology in the sixteenth century, its guiding principle has been that “the dose makes the poison.” It is a rule that applies to the medicines used by patients worldwide many billions of times a day. The right dose of aspirin can be a therapeutic godsend, but consuming too much can be lethal. The principle even applies to foods: Large amounts of nutmeg or licorice are notoriously toxic.
The risk that a substance poses broadly depends on two factors: its inherent capacity to cause harm and one’s exposure to it. It is a simple idea, but even some presumptive professionals seem unable to grasp it – as evidenced by the decision by the International Agency for Research on Cancer (IARC), a component of the World Health Organization, to classify the commonly used herbicide 2,4-D as “possibly carcinogenic to humans.”
When it comes to herbicides, the IARC seems to be on a losing streak. The organization recently classified glyphosate, another popular herbicide, as “probably” carcinogenic, a conclusion at odds with those of regulatory agencies around the world.