Q: You have written several columns about orange oil and fumigation and why you prefer orange oil. Could you put all of your arguments in one column so I can make an intelligent decision on how to proceed?- T.S., Berkeley
A: For many years the primary method of controlling drywood termites was to use sulfuryl fluoride (Vikane) as a fumigant. The house had to be wrapped and sealed and the gas injected. It was, and still is, a major inconvenience for homeowners, as they have to do a lot to prepare for the fumigation as well as stay out of the house overnight.
It was thought that once the house was cleared, the fumigant would dissipate harmlessly into the atmosphere. A recent study by UC Irvine has destroyed that myth. It turns out that sulfuryl fluoride is a major greenhouse gas that can last about 30 years in the atmosphere and may last 100 years. This study can be found at links.sfgate.com/ZFZO.
A study by the Scripps Institution of Oceanography confirms Irvine's findings. It can be found at links.sfgate.com/ZIXD. The Scripps study says researchers calculated that 1 kilogram of sulfuryl fluoride emitted into the atmosphere has a global warming potential approximately 4,800 times greater than 1 kilogram of carbon dioxide. That is pretty impressive.
Also, homes and commercial buildings are built differently now than when sulfuryl fluoride was in its prime. The homes made today are constructed much more tightly to control energy, and that can impede the flow of gas throughout the building, leaving some areas untreated.
Another important fact about sulfuryl fluoride is that when it breaks down, it leaves fluoride in the soil and in your home. Fluoride has been linked to poisonings and a few deaths. Inhaled fluoride has been implicated in acute respiratory failure.
Finally, homes fumigated with sulfuryl fluoride are likely to get reinfested. This is not the case when a house is treated with orange oil and the wood in the house treated with a sodium borate or silica gel.
We are a decade into the 21st century, and we need to get away from using toxic pesticides whenever we have a pest problem. Consider:
-- Crop losses caused by pesticides cost farmers and producers approximately $1.4 billion yearly; bird losses due to pesticides ring up at $2.2 billion yearly; and groundwater contamination at $2 billion yearly. ("Pesticide Impact on the Environment" by Cornell University Professor David Pimentel; 2005)
-- It is estimated that often less than 0.1 percent of an applied pesticide reaches the target pest, leaving 99.9 percent as an unintended pollutant in the environment. ("Environmental Impact of Pesticides Commonly Used on Urban Landscapes," by Jess Silver and Becky Riley; 2001)
-- According to Thomas Kerns, author of "Environmentally Induced Illnesses," pesticides may be responsible for many "adverse health effects," including cancer, immune system dysfunction, neural damage such as Parkinson's disease and respiratory disorders.
-- Studies have found that pesticide residue can be found not only in yards and outside areas where children and adults play and sit but also on household items such as carpets, toys, pillows, bedding, furniture and other items. ("Pesticides," the Mid-Atlantic Center for Children's Health and the Environment; 2008)
-- A 2007 article in the Los Angeles Times reported that women who lived near California farm fields sprayed with organochlorine pesticides were more likely to give birth to autistic children.
Don't even consider fumigating your house with sulfuryl fluoride. I think it would be a good idea to prohibit the use of any pesticides in or near schools, day care centers, retirement centers, hospitals and similar places. There are safer alternatives to fumigation, such as orange oil, and there are safer alternatives to all pest problems than using toxic pesticides.
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This article appeared on page E - 6 of the San Francisco Chronicle