Description

Diphacinone is a restricted use rodenticide in the indandione family, used in and around buildings, sewers, landfills and in agricultural settings. Diphacinone, an anticoagulant, causes bleeding and blood-thinning. It is more effective against rats than mice. Children may come into contact with diphacinone in its powder, pellet or bait forms. It should never be used anywhere near children!

Diphacinone is also used for medical purposes.

Health Effects

Immediate Health Effects

If SWALLOWED, diphacinone is Very Highly Toxic
If ABSORBED THROUGH SKIN, diphacinone is Very Highly Toxic
If INHALED (SNIFFED OR BREATHED IN), diphacinone is Highly Toxic

Longterm or Delayed Health Effects

This chemical is considered an Unclassifiable Carcinogen by the World Health Organization, the U.S. Environmental Protection Agency, or another agency.

Other

Hemorrhaging (bleeding), bloody discharge from nose, gums and eyes, loss of fluids, bloody stools and urine, coughing up blood, anemia, bruising.
Eye irritation.
Neurotoxin.
Can cause kidney and liver damage.
Can cause cardiopulmonary and neurologic injury in laboratory rats leading to death before hemorrhaging occurs. These symptoms have not been seen in humans.
Symptoms usually begin several days after ingestion.
Although no cases of developmental defects following the use of anticoagulants as rodenticides have been reported, anticoagulants prescribed for medical purposes can cross the placenta and are not recommended during pregnancy. Chemicals in the same class as diphacinone are excreted in breast milk.

How Exposures Occur

Accidental Ingestion

Because diphacinone may be applied in liquid, pellet or powder forms, a child could either touch the poison with his fingers, which could be swallowed when fingers are put in the mouth, or he could attempt to eat pellets or powder directly. Baits containing diphacinone that are not childproof could be opened by the child, who may then eat the poison.

Prenatal Exposure

The same chemical found in diphacinone is prescribed by medically for anti-clotting purposes. If a woman becomes pregnant while taking the medication, the chances of problems with the fetus are high.

Significant Statistics

Diphacinone is significantly more toxic than anticoagulant rodenticides developed earlier.

Whisson, Desley. Rodenticides for Control of Norway Rats, Roof Rats and House Mice. University of California. July 1996. http://animalscience.ucdavis.edu/Avian/pfs23.htm.

Rodenticides are intended to kill mammals making them particularly toxic to non-target species such as pets and wild predators. Since rodents have developed resistance to some rodenticides, manufacturers must create more toxic ones. The newer poisons are also a bigger risk to humans.

Fishel, Frederick M. Pesticide Toxicity Profile: Coumarin and Indandione Rodenticides. University of Florida. 2009. http://edis.ifas.ufl.edu/pi113.

Solutions

How to detect diphacinone

As of the 1998 Reregistration Eligibility Decision, the U.S. EPA will require that manufacturers of diphacinone incorporate an indicator dye, to help identify whether a child or pet has actually consumed the pesticide, and a bittering agent into the formulations. This should ensure that only children who are known to have swallowed the rodent poison are treated. (Some children receive the treatment as a precaution in cases where it is suspected, but not proven, that they have swallowed the poison.)
Know the ingredients of the rodenticide you are using. Read labels to determine if diphacinone is in products in your home or check PAN’s Pesticide Database for a list of brands and products containing this pesticide. If you hire a professional exterminator, ask for safety information, such as a Material Safety Data Sheet (MSDS) for the products used. New home owners should inspect carefully for rodenticide baits that may have been left by a previous owner.

How to minimize exposure to diphacinone

If your child swallows this rodenticide, contact a poison control center immediately.

Alternatives

Make your home unwelcoming to rodents. Eliminate the source of their livelihood, food and water, indoors and outdoors.
Block the rodent "doorways" to prevent entry. Cover holes with rodent-resistant materials, such as sheet metal (26 gauge or heavier), perforated metal (24 gauge or heavier with openings no more than 1/4 inch), hardware cloth (19 gauge or heavier with openings no more than 1/4 inch), brick with mortared joints, cement mortar (1:3 mixture ) or concrete (1:2:4 mixture).
Set a trap for the pesky mice or rats. Baited traps, such as snap traps, glueboards, and live animal traps, don’t require poisons. (Some glueboards and other traps may use pesticides. Avoid these!) Place the traps where rodents have been seen and near entry points. Remember to check them daily.

For More information

Books, articles, factsheets and reports

Stein, Dan. "Controlling Rats Without Poisons." Eugene, OR: Northwest Coalition for Alternatives to Pesticides, April 2007. http://www.pesticide.org/pubs/alts/rodents/rats.html

Protecting Children from Pesticides. U.S. Environmental Protection Agency, Office of Pesticide Programs, January 2002.

http://www.epa.gov/pesticides/factsheets/kidpesticide.htm

ChemicalWatch Factsheet: Rodenticides. Beyond Pesticides. 2000-2001. http://www.beyondpesticides.org/pesticides/factsheets/Rodenticides.pdf.