Toxicants & Fumigants

A toxicant is a poisonous substance – it causes harm  and even death of an organism. A fumigant is a a type of toxicant. It is a pesticide that volatilizes, forming a toxic vapor or gas that kills in the gaseous state. Regulations regarding the use of toxicants change over time as new products are developed and research has new findings. In particular, due to the risk and number of poisonings from rodenticides, consumer use of some products is being reconsidered. Read labels before purchasing any toxicant to make sure that you can legally use it as the label directs. Some require training and state certification as a pesticide applicator prior to use.

For a professional discussion of Chemical Controls visit http://nwco.net 

Definitions – See Glossary

Toxicant – substance used to poison a problem animal, typically through ingestion, although it can be inhaled as a gas.

Fumigant – gas used to poison a nuisance animal as it breathes.

General Use Pesticides (GUP) – may be purchased over-the-counter.

Restricted Use Pesticides (RUP) – require a pesticide applicator’s license to purchase and use.

Secondary poisoning – Injury to an organism that ate the animal that was poisoned originally.

Facts about Pesticides

• No one can guarantee where a poisoned animal will die.
• No pesticide can be called “SAFE”. You can only use pesticides more safely or less safely.
• Most negative incidents with toxicants, including fumigants, occur because the applicator failed to follow the instructions on the label.

Fumigants

1. Phosphine Gas

• Phostoxin– Degesch America
  • Fumigation Management Plan (FMP) is required when using this product.

2. Charcoal-Potassium Nitrate

Used as a rodent fumigant in burrows, carbon (charcoal) formulated with several other pesticide active ingredients (sodium and potassium nitrates and sulfur), is used in pyrotechnic fumigant gas cartridge products. When a cartridge is ignited and placed in a pest burrow, it produces carbon monoxide and other gases that kill target pests.

Toxicants in Rodenticides

Anticoagulants

First Generation	Active Ingredient	Feeding
	Warfarin	Multi-feed
	Chlorophacinone	Multi-feed
	Diphacinone	Multi-feed
Second Generation
	Brodifacoum	Single Feed
	Bromadiolone	Single Feed
	Difenacoum	Single Feed
	Difethialone	Single Feed

Non-Anticoagulants

Active Ingredient	Feeding	Mode of Action
Bromethalin	Single Feed	Interferes with the animal’s nervous system
Cholecalciferol	Single Feed	Causes internal bleeding and kidney injury by increasing calcium levels to  a lethal level
Zinc Phosphide	Single Feed	Blocks cells from making energy, and the cells die

Resources

Bait Station Use – 2012. Univ. of Nebraska-Lincoln

Restrictions on Rodenticide Products – 2021. US EPA 

Rodenticides – National Pesticide Information Center (NPIC)

Rodenticide Fact Sheet – National Pesticide Information Center (NPIC)