Crystalline in nature, chlorpyrifos is a form of organophosphate insecticide that is widely used in both agricultural and home settings. Organophosphates (sometimes abbreviated OP) are a common name for phosphoric acid esters. This insecticide is marketed under several different brand names including: Dursban, Brodan, Scout, Detmol UA, Stipend, Empire, Paqeant, Dowco 179, Lorsban, Piridane, and Eradex.  The chemical works by inhibiting acetylcholinesterase (AChE), which is an enzyme that degrades neurotransmitters.

Chlorpyrifos is termed a broad spectrum product that has been used for many years for many different purposes. It can be applied inside and outside the home, and currently, it can be purchased for both home and commercial use.  Inside the home it is commonly used to control fleas, bedbugs, biting insects, mosquitoes, and termites. Outside the home, it is used to treat crops such as corn, wheat, cotton, peanuts, and various other types of vegetables.

Side effects on humans

ChlorpyrifosChlorpyrifos is considered to be moderately toxic to humans (Class II) and has been directly linked to neurological complications, developmental disorders, and autoimmune conditions. Because it is a type of neurotoxin, it can cause the transmission of nerve impulses to become disrupted. When this happens, headaches, dizziness, increased urination, loss of motion, and drooling can occur.  If exposure has been excessive, convulsions, paralysis, and even death can result. Chlorpyrifos is classified as an endocrine disruptor, which can cause detrimental effects on the hormonal system as well.

Due to the fact that chlorpyrifos can enter the body just by breathing, children are highly affected by the chemical. Cases of asthma, mental developmental issues, and ADHD have been observed in children exposed to the chemical. Low birth weight has been attributed to chlorpyrifos when pregnant women have been exposed. Respiratory, heart, and intestinal system muscles are also affected by the chemical. Overall side effects vary, but can range in severity from a mild twitch to full convulsions.

Toxicity on other life forms

In addition to its toxic effect on humans, chlorpyrifos is also considered to be highly toxic to aquatic life, especially fish, amphibians, and bees. Scientific studies have found that as the chemical breaks down naturally in the environment, it releases chlorpyrifos oxon, which has been found to be even more toxic than the original form of the chemical.


Above – Chlorpyrifos is often mixed into an oil based liquid at a 21% solution. Application of this chemical should only be conducted by a trained person.

Chlorpyrifos is not water soluble, and must be mixed with an oil based material prior to application. The chemical comes in a white, solid, crystalline form and is most commonly applied by means of spraying. Despite the many risks and reactions to the product, this chemical is currently still quite widely used around the world as a termiticide as well as for general insect pest control. Further technical specifications on chlorpyrifos can be found here.

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