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CAS 51-03-6

Piperonyl butoxide

Piperonyl butoxide (PBO) is a chemical added to many insecticides to make them work better. It’s used in homes, on pets, on crops, and for mosquito control, so many people may encounter small amounts [1][2].

Where It Comes From

A manufactured “synergist” mixed with pyrethrins/pyrethroids in sprays, foggers, pet shampoos, and agricultural/public health products [1][2].

How You Are Exposed

Breathing spray or indoor residues during/after use, touching treated surfaces or pets, eating trace residues on food, or on the job when mixing/applying pesticides [1][2].

Why It Matters

Short-term exposure can irritate eyes/skin and cause headache, dizziness, or nausea; high doses in animals affect the liver and thyroid hormones. EPA notes suggestive evidence of cancer based on mouse liver tumors; human evidence is limited [1][2][3].

Who Is at Risk

Pesticide applicators; infants and children; people with asthma or chemical sensitivities; pregnant people; residents where indoor spraying is frequent [1][2].

How to Lower Your Exposure

Use integrated pest management; try non-chemical controls first. Follow labels, avoid space/room foggers when possible, ventilate well, and keep children/pets out until sprays dry. Wash hands and rinse/peel produce. Ask for PBO-free options when feasible [1][3].

References

  1. [1]U.S. EPA. Piperonyl Butoxide: Human Health Risk Assessment for Registration Review (Office of Pesticide Programs, 2019/2021).
  2. [2]WHO/FAO Joint Meeting on Pesticide Residues (JMPR). Piperonyl butoxide: toxicological evaluation and ADI (1995/1997).
  3. [3]U.S. EPA. Reregistration Eligibility Decision (RED) for Piperonyl Butoxide (2006).

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