Your House Has Termites, Part 2: Now what?

Editors Note: In the spring issue of this magazine, Dr. Susan Kegley focused on the use of Vikane — Dow's sulfuryl fluoride product — for termite treatments. In this follow-up article, she examines what can go wrong when homes are fumigated, and discusses available alternatives to Vikane fumigation.

Fumigating your home: what can go wrong?

Many things, unfortunately. Fumigation is a difficult pesticide application to perform without making mistakes that may have very serious consequences. Tarps must be installed correctly so they don't leak, and the fumigator must accurately determine the appropriate amount of gas to use. Failure to air out the house completely is a frequent cause of poisonings in situations where the pest control operator has incorrectly told residents that it is safe to reenter their house.

Regulatory agencies and the courts have found that repeated violations of fumigation safety have occurred during sulfuryl fluoride treatments. According to one judge, the practices of one major extermination company were “nothing short of scary.” [1] Adequate pre-fumigation preparation is also a major hassle. You will need to remove (preferably) or else securely package food items, pillows, cushions, clothes in closets, and any other items that can trap air (a category that is much larger than most people realize) so that they are not contaminated.

Isn't there something else they can do besides use a chemical that is so toxic I have to leave my home for a week?

Yes. There are several effective non-chemical techniques that can effectively treat infestations of drywood termites. [2] Heat is perhaps the best option for treating a whole structure. This method works by heating the entire structure to a minimum of 120°F and holding that temperature for half an hour or more, a level that no termites can survive. For maximum effectiveness, it is important to pay special attention to very large beams and wood that is part of tiled or concrete areas to ensure these areas are heated to the desired temperature. Preparation for heat treatment involves removing any potentially flammable or heat-sensitive items in your home such as candles, fuels, and sensitive electronics. There is no need to wait before entering the structure after a heat treatment, or to move out of your home for days at a time. Heat treatments can also be used to selectively treat particular sections of a home, or a single apartment or condominium unit.

Effective spot treatments of termite-infested areas can also be done with microwave treatments, or through injection of liquid nitrogen, which kills the termites by freezing them. In easily accessible areas, replacing the infested wood with new wood is effective and inexpensive. Detection devices are now available to make it easy to find all active termite colonies. [3]

I've heard this chemical is now being used to fumigate stored grains and dried fruits and nuts. Can eating food treated with sulfuryl fluoride hurt my family or me?

When sulfuryl fluoride breaks down, it forms fluoride, the same substance dentists use to make teeth resistant to cavities. According to most current studies, at very low levels comparable to what is added to water supplies or less, fluoride is not generally thought to be harmful (although we consider this an area where the science bears watching). But exposures to even slightly higher amounts can make bones brittle and cause white stains on teeth. Furthermore, some animal studies show increased incidence of bone cancers with exposure to fluoride, and fluoride is known to cause birth defects when the developing fetus is exposed. [4] So it is likely that these new uses of sulfuryl fluoride for food fumigation will lead to much higher levels of fluoride in the food supply, which is definitely a cause for concern.

Dr. Susan E. Kegley is Senior Scientist at PANNA and heads the Science and Information Department.

References

1. Cox, C. Summer 1997. Fumigant Fact Sheet: Sulfuryl Fluoride, Journal of Pesticide Reform, Vol.17, No. 2, http://www.pesticide.org/sulfuryl.pdf.

2. University of California IPM Online. September 2002. Pests of Homes, Structures, People, and Pets: Drywood Termites, UC ANR publication 744, http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7440.html.

3. Search and Destroy, Termite Detection Systems, Inc. http://www.termitedetector.com/home.php.

4. California Department of Pesticide Regulation. June 2005. Sulfuryl Fluoride Risk Characterization Document, http://www.cdpr.ca.gov/docs/empm/pubs/tac/draftrcd.htm.