Here is an answer from Our Water our World addressing your question.

"There is always some risk if a pesticide is used. So we are not allowed to say that any pesticide is safe.

However, if you have drywood termites, totally non-chemical treatments are available. These include heat, electrogun, and microwaves. These can be effective if the termite colonies are accessible.

Another possibility for drywood termites is chemical injection. About 70% of the time in California, drywood termites are treated by this method. This is usually the least expensive method. Holes are drilled and chemicals are injected into the colony. One chemical treatment uses Timbor, which is a mixture of boric acid and borax. Others include Premise and Termidor. Generally, your risks are low when chemicals are injected. You are not exposed to an aerosol, and chemicals remain inside the wood.

About 10% of the time in CA, the non-chemical methods are used. These cost a little more than chemicals, but cost less than a fumigation.

About 20% of the time fumigation has to be used because the colonies are so extensive that local treatments with chemicals become prohibitively expensive.

If you have subterranean termites, the possibilities are termite baits, a chemical ground treatment, and treatment of the structure. Termite baits have fewest possible environmental impacts. However, they take 3-6 months and are not 100% reliable. Chemical ground treatments use low concentrations of 0.05% or 0.06% of active ingredients. Premise and Termidor, which are brandnames of these products, can be very effective. They are injected into the soil, they bind to soil, and are not likely water pollutants. Subsurface injection means that your chance of exposure is low.

Treatment of the structure with Timbor keeps termites from eating treated wood, and subterranean termites do not tunnel over it. This treatment is best for crawl space construction where the surfaces of unpainted joists, etc. can be treated. "