The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Aluminum phosphide (also magnesium phosphide)
- Chemical class
- A phosphide fumigant. The solid is not the active gas: aluminum phosphide reacts with moisture from the air, water, acids and many other liquids to release hydrogen phosphide (phosphine). Each Weevil-Cide tablet weighs about 3 grams and releases 1 gram of phosphine.[1][2]
- Mode of action
- IRAC Group 24A: Mitochondrial complex IV electron transport inhibitors (phosphides, which release phosphine)[4]
- Signal word
- Weevil-Cide Tablets: Danger-Poison[1]
Why it isn't used next to houses
In April 2010, after two deaths in Utah, EPA expanded the restrictions on phosphide products used against burrowing rodents and directed registrants to amend their labels.[3]
EPA's 2010 restrictions prohibited use around all residential areas, including single- and multi-family homes, nursing homes, schools (except athletic fields), day care facilities and hospitals, and raised the buffer around other buildings that people or domestic animals may occupy from 15 feet to 100 feet.[2]
The current Weevil-Cide label, stamped March 1, 2024, strictly prohibits use within 100 feet of any building where people or domestic animals do or may live on residential properties, nursing homes, schools (except athletic fields), day care facilities and hospitals. Burrows within 25 feet of sheds and other uninhabited structures can't be treated, nor can burrows that open under or into occupied buildings or that could let gas travel through pipes or conduits.[1]
In athletic fields and parks, the applicator must post DANGER/PELIGRO signs with a skull and crossbones and the words DO NOT ENTER at the entrances, and the signs stay up at least 2 days after the final treatment.[1]
Magnesium phosphide
Magnesium phosphide works the same way, reacting with moisture to release phosphine. It is also a restricted use pesticide, and EPA's 2010 burrow restrictions apply to both.[2]
California has restricted aluminum and magnesium phosphide products since 2005.[3]
Where it is used
Aluminum and magnesium phosphide are used mainly to fumigate stored raw agricultural commodities, animal feed, processed foods and nonfood commodities in sealed containers or structures. Outdoors, they are used to fumigate the burrows of rodents and moles.[2]
Only certified applicators, or people trained for burrow control and working under their direct supervision, may apply it. EPA notes that indoor use of these burrow products has long been prohibited, and the label requires every burrow treatment to be made outdoors.[1][2]
For open burrow systems the applicator drops 2 to 4 tablets into each entrance, plugs it with crumpled paper and soil, and seals the untreated entrances. For pocket gophers and moles the tablets go down a probe hole into the main runway, and the label says not to treat if the soil is extremely dry or there is no sign of recent activity.[1]
Before any phosphine application, burrow fumigation included, the certified applicator and the property owner must write a fumigant management plan that describes the treatment area and every safety requirement, and the applicator must give the customer a copy before treating a burrow.[2][1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Weevil-Cide Tablets[1] | UPL NA, Inc. | 70506-13 | 60.0% | tablets that release phosphine gas (Restricted Use Pesticide) | Danger-Poison |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Weevil-Cide Tablets | Outdoor rodent and mole burrow systems (certified applicators only) | Woodchucks, marmots, prairie dogs (not Utah prairie dogs), roof rats, mice, ground squirrels, moles, voles, pocket gophers and chipmunks | 2–4 tablets per burrow entrance or probe hole[1] Lower rate for small burrows or moist soil, higher for large systems or drier soil. Never within 100 feet of a building where people or domestic animals do or may live on residential properties. |
Safety and environmental hazards
People
Signal word DANGER/PELIGRO - POISON, and restricted use because of the high acute inhalation toxicity of phosphine gas. The label lists headaches, dizziness, nausea, difficult breathing, vomiting and diarrhea as symptoms of exposure, and severe poisoning can show up within a few hours to several days as fluid in the lungs, leading to unconsciousness and death. EPA expanded the burrow restrictions in 2010 after two deaths in Utah.[1][3]
Pets
The label's 100-foot no-use zone covers any building where people or domestic animals do or may live, and the label warns that non-target animals exposed to phosphine gas in burrows will be killed.[1]
Bees and pollinators
The label lists destroying bees, including Africanized bees and diseased colonies, among its uses, along with fumigating stored beehives and beekeeping equipment for greater wax moth.[1]
Fish and water
The label says the product is toxic to wildlife and must not be applied directly to water or to wetlands such as swamps, bogs, marshes and potholes, and that water must not be contaminated when equipment is cleaned or wastes are disposed of.[1]
Common questions
- Can I buy aluminum phosphide to gas gophers or moles in my yard?
- No. It is a restricted use pesticide sold only to dealers and certified applicators, and the label strictly prohibits use within 100 feet of any building where people or domestic animals do or may live on residential properties.[1]
- What are the symptoms of phosphine poisoning?
- The label lists headaches, dizziness, nausea, difficult breathing, vomiting and diarrhea. Mild exposure can cause a general sick feeling, ringing in the ears, fatigue, nausea and chest pressure that ease in fresh air, while severe poisoning can appear hours to days later as fluid in the lungs. Get medical attention immediately for any overexposure.[1]
- Does phosphine gas always smell like garlic?
- No. Pure phosphine is odorless; the garlic odor comes from a contaminant, and the label warns that the absence of a garlic odor does not mean the gas is absent.[1]
- What should I do if someone swallows a tablet?
- Call a poison control center or doctor immediately. The label says not to induce vomiting unless told to, because vomit can give off phosphine and expose others, and not to give water unless a physician authorizes it, since water can form more phosphine.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Weevil-Cide Tablets label, EPA Reg. No. 70506-13 (EPA-stamped, Mar. 1, 2024).” www3.epa.gov/pesticides/chem_search/ppls/070506-00013-20240301.pdf (accessed 2026-11-08)
- U.S. EPA, “Expanding Use Restrictions to Reduce Risks of Aluminum and Magnesium Phosphide (2010; archived page).” archive.epa.gov/pesticides/reregistration/web/html/aluminum-magnsm-phos-fs.html (accessed 2026-11-08)
- California Department of Pesticide Regulation, “Update: Aluminum and Magnesium Phosphide Rodenticides/New Approved Labeling Amendments and Questions and Answers (letter to county agricultural commissioners).” www.cdpr.ca.gov/cac-letter/update-aluminum-and-magnesium-phosphide-rodenticides-new-approved-labeling-amendments-and-questions-and-answers (accessed 2026-11-08)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-11-08)