Permethrin is not the worst poison you could use in your garden. It is of low toxicity to humans. But:
Class and Uses: Permethin is a synthetic pyrethroid. Pyrethrins are derived from crysanthemums, but the synthetic ones are much more concentrated and toxic. It is a broad spectrum insecticide that has been sprayed widely in mosquito abatement programs and used for lice, ticks, and scabies and on a variety of crops. It is a neurotoxin, which acts on the nervous system of insects and causes muscles to spasm, culminating in paralysis and death
Animal toxicity: Permethrin is highly toxic to both freshwater and estuarine aquatic organisms. Most agricultural, public health, and down-the-drain scenarios modeled resulted in exceedances in the acute risk quotient (RQ) for freshwater and estuarine fish, invertebrates, and sediment organisms. It is also extremely toxic to honeybees, as well as other beneficial insects. . Severe losses may be expected if bees are present at treatment time, or within a day thereafter . Permethrin is also toxic to wildlife . It should not be applied, or allowed to drift, to crops or weeds in which active foraging takes place.
It is less toxic to mammals than insects and aquatic organisms, but cats are especially sensitive to it and it is dangerously toxic to them.
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