Description

Bromethalin is a restricted use rodenticide used in and around buildings and sewers, and inside transportation and cargo vehicles. Bromethalin poisons the nervous system by blocking nerve activity, which leads to death. It is extremely toxic. Only a single dose of bromethalin is needed to cause death, unlike other rodent poisons, such as diphacinone and warfarin, which are anticoagulants (blood thinners) that work over time. Bromethalin is frequently swallowed by children accidentally. The brightly colored baits, which have a food-like taste and smell, are often placed in areas where children and pets can reach them, such as underneath radiators, ovens, near refrigerators or trash.

In order to reduce the risk to children, the EPA requires that all rodenticides sold to consumers must be in bait stations and not sold as loose pellets.

Health Effects

Immediate Health Effects

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

Longterm or Delayed Health Effects

Neurotoxin = Can harm brain and central nervous system

Other

Loss of muscle control, weakness, loss of tactile sensation.
Swelling of the brain, spinal column and nerves; blurred vision; loss of consciousness.
Skin and eye irritation, nasal discharge.
Death by respiratory arrest.

How Exposures Occur

Accidental Exposure

Children and pets could swallow the poison if it is placed within their reach and/or if the the bait is not in a tamper-resistant station. Children are attracted by the brightly colored baits.

During Application

Oral or inhalation exposure when setting the poison is primarily a greater concern for adults.

Significant Statistics

Bromethalin was developed in 1985 to replace the anticoagulant rodenticides when some rodents developed resistance.

Klausen, Paul. Bromethalin. Animal Disease Diagnostic Laboratory. Spring 1997. http://www.addl.purdue.edu/newsletters/1997/spring/bromoethalin.shtml.

In 2008 there were 529 exposures to bromethalin, and 392 of those were in children under age 6.

Bronstein, Alvin C, M.D., et al. ”2008 Annual Report of the American Association of Poison Control Centers’ National Poison Data System (NPDS): 26th Annual Report.” Clinical Toxicology. Vol. 47, No. 10 (2009).

http://www.aapcc.org/dnn/Portals/0/2008annualreport.pdf.

Solutions

How to detect bromethalin

As of the 1998 Reregistration Eligibility Decision, the U.S. Environmental Protection Agency will require that manufacturers of bromethalin incorporate an indicator dye and a bittering agent in its formulations. The dye will help identify whether a child or pet has actually consumed the pesticide, and 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.) The bittering agent tastes bad and will hopefully deter children from ingesting bromethalin.
Know the ingredients of the rodenticide you are using. Read labels to determine if bromethalin is in products in your home or check Pesticide Action Network’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 bromethalin

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

Alternatives

Make your home unwelcome to rodents. Eliminate access to food and water, indoors and outdoors. Use rodent-proof containers. Cover or store pet food dishes when not in use. Keep wood piles off the ground and away from the house. Cut tall grasses and weeds near the house. Clean-up and recycle trash.
Block rodent doorways to prevent entry. Cover holes (e.g., where pipes or cables enter the house) 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). Use weather-stripping under doors.
Set a trap for the pesky mice or rats. Baited traps, such as snap traps, glueboards, and live animal traps, don’t require poisons. Place them where rodents have been seen and near entry points. Remember to check them daily.

For More information

Books, articles, factsheets and reports

Chemical Watch Factsheet: Rodenticides. Beyond Pesticides. Vol 20, No. 4 (2000-2001). http://www.beyondpesticides.org/pesticides/factsheets/Rodenticides.pdf.

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.

Cox, Caroline. ”A Mouse- and Pesticide-Free Home.” Journal of Pesticide Reform, Vol. 24, No. 1 (Spring 2004). http://www.pesticide.org/mice.pdf.