Parathion

Parathion was synthesized in Germany in 1944 as part of Bayer's organophosphate research program, which had grown from the nerve agent work of Gerhard Schrader [1]. Released for agricultural use after the war, parathion's extreme effectiveness against insects made it one of the most widely adopted insecticides of the 1950s–1970s, used on fruits, vegetables, cotton, and grain. Its acute mammalian toxicity was clear from the start — it is approximately 10 times more toxic to mammals than malathion — yet regulatory action was slow [2]. Dozens of US farmworkers died from parathion poisoning each year during peak use, and in developing countries the death toll was far higher. EPA cancelled most US uses in 1991 after safer alternatives became available. It remains in use in some agricultural settings globally [3].

Agricultural workers who apply parathion or work in recently treated fields face the primary contemporary exposures [1]. Parathion is readily absorbed through intact skin — farmworker poisonings frequently occurred through dermal contact with wet foliage or contaminated clothing. Dietary residues in conventionally grown produce are regulated but have been a concern in crops with high application rates [2]. Accidental ingestion remains a risk where the compound is improperly stored — it has no warning odor, and cases of deliberate or accidental poisoning by adding it to food or beverages have occurred [3].

Parathion inhibits acetylcholinesterase and butyrylcholinesterase with very high potency — the OSHA permissible exposure limit is 0.1 mg/m³, reflecting its extreme acute toxicity [1]. The clinical progression of parathion poisoning is classic organophosphate toxidrome: miosis, salivation, lacrimation, urinary and fecal incontinence, bradycardia, bronchospasm, and seizures — potentially fatal within hours without treatment. Children are disproportionately affected because they lack mature oxonase detoxification capacity [2]. Subchronic exposures that do not produce acute symptoms cause delayed neurotoxicity affecting cognitive function and behavior in children [3].

Agricultural workers in countries where parathion remains in use face acute poisoning risk [1]. US farmworkers may face exposure if parathion is illegally applied or if they import food from high-use regions. Children in agricultural families and communities near fields have heightened vulnerability to organophosphate effects [2].

If you suspect illegal pesticide use in your workplace, contact the EPA or your state agricultural department's pesticide division [1]. Choose organic produce for high-residue crops. If parathion poisoning is suspected, immediately move the exposed person to fresh air, remove contaminated clothing, rinse skin with soap and water, and call 911 — atropine and pralidoxime are the specific antidotes [2]. Workers applying any organophosphate should have baseline cholinesterase testing and periodic monitoring [3].