Under emergency rules imposed by the state Environmental Protection Agency, California homeowners will pay more to have their houses fumigated for termites and will have to stay out longer after the treatment to avoid potentially harmful levels of toxic gas.
The new rules were imposed last month, after two studies showed that both types of gas used in California's 150,000 annual fumigations for drywood termites remain in structures longer than previously believed.
Two other studies showed that the fumigant used most often in Southern California, methyl bromide, caused birth defects in animals exposed to high doses of the chemical. State officials said there is no evidence that methyl bromide causes birth defects in humans, but the length of time houses are aired out after fumigation is being extended as a precaution.
The emergency regulations were imposed following the deaths of two Redwood City residents after their apartment house was fumigated with methyl bromide. But Cal EPA spokeswoman Veda Federighi said the new rules were not prompted by the deaths. The state had been working on the new regulations for several months before the victims died, she said.
The Jan. 17 death of Gary Barthold was attributed methyl bromide intoxication. The March 31 death of Kathy Monahan, Barthold's roommate, is still under investigation. Officials are also studying whether proper procedures were used by the fumigation company.
It has been more than a dozen years since a death occurred after a building had been cleared for re-entry. Several other deaths occurred when people deliberately entered houses while they were being fumigated. Those victims were either burglars or people who were drunk or trying to commit suicide, according to state officials.
In Southern California, most fumigations are done when a home is sold, because mortgage lenders require a report showing that any termites in a house have been eradicated, said John Munro, administrative assistant at the Pest Control Operators of California, an industry trade group. Home sellers typically want to save money and use the cheaper methyl bromide treatment, he said.
But many pest control operators are now switching to the more expensive fumigant, Vikane (sulfuryl fluoride), because it has a shorter waiting period after fumigation before occupants can re-enter a building.
Under the new regulations--which are temporary until additional tests are completed--fumigations with Vikane will require residents to stay out of the house for one or two days, while four days are usually needed for methyl bromide fumigations. The length of time depends on whether fans are used to help ventilate the house, and results of air tests to determine how much gas, if any, remains.
Previously, people usually only had to leave the house for about 24 hours.
Orkin spokeswoman Judith Donner said staying out of the house for the extra 72 hours is "a really big inconvenience to customers," so the Atlanta-based company has stopped using methyl bromide.
Consumers will pay about 25% more for a fumigation because of the higher cost of Vikane, as well as the extra labor required to make additional visits to check the house, said Lee Blevins, president of Antimite , a Rancho Cucamonga-based pest control company.
A fumigation for a one-story house with 2,000 square feet of living space and a detached garage would have cost about $900 before the changes, Blevins said. The new price is about $1,120, he said.
Besides longer aeration periods, the state's new interim regulations also require that lower levels of methyl bromide be reached before a building is cleared for re-entry. The level previously considered safe was five parts per million. But one study found levels rise after residents enter a home and close windows and doors.
Levels tend to rise as gas continues to seep out of furniture and walls, particularly areas with little air circulation.
The levels for methyl bromide have now been lowered to three parts per million, and fumigators must test air inside the walls, where gas levels may be higher than inside the room.
Rudolf Scheffrahn, a University of Florida associate professor who did one of the studies, said while levels of both fumigants can rise sharply, they don't remain high for very long.
He said that in the worst-case scenario, where a person immediately re-enters the house after it is cleared for re-entry and closes all windows and doors, the levels peaked within 90 minutes of closing up the house, then dropped.
However, concerns about a different study, which found birth defects in animals exposed to high levels of methyl bromide, led officials to decide on a longer waiting period, said Federighi, who is with Cal EPA's department of pesticide regulation.