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CAS 150-50-5

Merphos

Merphos is an organophosphate pesticide/defoliant used mainly in cotton production. It inhibits cholinesterase, a nerve enzyme, so exposure can quickly cause nervous-system symptoms [1][2][3].

Where It Comes From

Agricultural use as a cotton defoliant and from storage or disposal of older pesticide products; manufacturing sites [1][2].

How You Are Exposed

Skin contact or inhalation during mixing or spraying; drift from nearby fields; touching treated plants/equipment; contaminated dust, food, or water [1][2][3].

Why It Matters

Cholinesterase inhibition can cause headache, nausea, sweating, blurred vision, weakness; severe poisoning may lead to breathing problems, seizures, and can be fatal. Repeated exposures can depress cholinesterase levels [2][3].

Who Is at Risk

Pesticide handlers and farmworkers, people entering fields before re-entry times, residents near treated fields, children, and pregnant people [1][3].

How to Lower Your Exposure

Follow label and re-entry intervals; use proper protective gear; avoid fields during and shortly after application; close windows during spraying; wash hands, remove shoes, and launder work clothes separately; rinse/peel produce [1][3].

References

  1. [1]U.S. EPA. Tribufos (DEF) pesticide risk assessments and registration documents (cholinesterase-inhibiting cotton defoliant).
  2. [2]CDC/NIOSH Pocket Guide to Chemical Hazards: Tribufos (DEF) – health effects, exposure routes, and protective measures.
  3. [3]ATSDR. Medical Management Guidelines for Organophosphate Insecticides – signs/symptoms and exposure reduction.

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