Hey Mr. Green,

I have a bad termite infestation, but I'm concerned that tenting might kill all the birds and insects that live in the large sycamore over my house.

—Rachel in Oak View, California

There is no need to worry about contaminating innocent outdoor critters provided that your termite assassins follow proper procedures. Make sure the company you hire guarantees very tight tenting so the active termite zapper, sulfuryl fluoride, doesn't leak outside. After the fumigation is complete, they should test the air inside to make sure the chemical is reduced to one part per million before anyone is allowed to enter the house. 

The Department of Entomology at the University of California, Riverside, examined fumigations at two single-family residences and found that concentrations of sulfuryl fluoride outside the house were negligible throughout the fumigation and aeration periods. Other studies have confirmed that the gas dissipates so rapidly that any exposure to birds and insects would be too brief to cause harm.

Remove any upholstered furniture from your house before fumigation to prevent dangerous levels of sulfuryl fluoride from hanging around. Studies have found that carpets left in the house could trap the chemical. Some experts recommend keeping pets away from carpet for several weeks after treatment.