What gas is used to poison rats? - briefly
Carbon monoxide is the gas most commonly employed to poison rats in sealed fumigation chambers. It displaces oxygen, causing rapid asphyxiation.
What gas is used to poison rats? - in detail
The gas most frequently employed for rodent eradication in sealed environments is carbon monoxide (CO). CO binds to hemoglobin with an affinity over 200 times that of oxygen, forming carboxyhemoglobin and preventing oxygen transport, leading to rapid hypoxic death. Commercial CO generators produce the gas by incomplete combustion of fuel, allowing precise concentration control between 5 % and 10 % by volume, which is lethal to rats within minutes.
Phosphine (PH₃) is another widely used fumigant. It is released when aluminum phosphide or magnesium phosphide tablets react with moisture. Phosphine penetrates dense materials, inhibits cellular respiration by disrupting cytochrome oxidase, and causes mortality at concentrations as low as 0.5 mg L⁻¹. Application typically involves placing tablets in an airtight container or storage area, then sealing for a prescribed exposure period (often 24–48 h).
Hydrogen cyanide (HCN) is less common due to extreme toxicity to humans but appears in specialized pest‑control formulations. HCN interferes with cytochrome c oxidase in the mitochondrial electron‑transport chain, halting ATP synthesis. Controlled releases achieve concentrations of 2–5 ppm, sufficient to kill rodents within a short timeframe. Strict regulatory limits govern its use, requiring trained personnel and ventilation safeguards.
Key considerations for any gaseous rodenticide include:
- Concentration monitoring: Use calibrated detectors to maintain lethal levels while avoiding excess that could compromise safety.
- Sealing integrity: Ensure all entry points, vents, and cracks are closed to prevent gas leakage and protect non‑target organisms.
- Exposure duration: Follow manufacturer guidelines; insufficient time may result in survival and potential resistance.
- Personal protective equipment (PPE): Respirators, gloves, and eye protection are mandatory during setup and removal.
- Regulatory compliance: Verify local pesticide regulations, as many jurisdictions restrict or ban certain gases for pest control.
In summary, carbon monoxide, phosphine, and, in limited cases, hydrogen cyanide constitute the primary gaseous agents used to exterminate rats, each with distinct mechanisms, application methods, and safety requirements.