Chlorpyrifos-methyl

Chlorpyrifos-methyl is a pesticide that’s commonly used on grain to protect it from pests such as weevils, worms, beetles and moths. It’s a crystalline organophosphate that’s been around since 1965, and that used to be available for home insecticide under the names Dursban and Lorsban. In 2001, the EPA cracked down on the pesticide because of possible toxicity, and Dow, its manufacturer, agreed to stop selling chlorpyrifos to be used in homes. It also restricted the use of the pesticide on crops. However, in other countries such as Iran, Dow is still allowed to market chlorpyrifos for use in the home, and still does so. Currently, the US uses 80,000 pounds of chlorpyrifos annually.

The EPA classifies chlorpyrifos in Class II, which means it’s known to be moderately toxic to humans and animals. Even in tiny amounts, the pesticide can have negative health effects: it can produce a condition called cholinesterase inhibition, which is an overstimulation of the nervous system. Symptoms of this condition include confusion, nausea and light-headedness. In higher amounts, it can paralyze the respiratory system and cause death. It’s also known to be harmful to the kidneys and liver, and can even cause loss of appetite and weight loss.

Chlorpyrifos is also bad for fetuses and children. Studies suggest that chlorpyrifos exposure in utero can have negative effects on a child’s motor skills and mental acuity, and can increase the risk of a child developing ADHD: one 2010 clinical trial demonstrated that with every tenfold increase in organophosphates in a child’s urine, that child had a 55% to 72% increased chance of having ADHD. Another study showed that chlorpyrifos exposure was connected to memory problems and low IQ in seven-year-olds. The chemical is also linked to lower birthweight and smaller infant head circumference.

This insecticide has even been implicated in Gulf War Syndrome. In 2011, researchers studied the effects of chlorpyrifos on the brain, and saw that the chemical altered the firing rates of neurons in a specific part of the brain linked to neurodegenerative conditions.

In 2004, the Centers for Disease Control and Prevention found chlorpyrifos metabolites – byproducts of the insecticide after it has been processed by the body – in 91% of the people it tested. A 2008 study found that when children switched to organic diets, the levels of chlorpyrifos metabolites in their urine dropped drastically.