An increasing number of insects have developed high levels of resistance to pyrethroids, such as cockroaches, head lice, and tobacco budworm, pear psylla, fall army-worm, German cockroach, spotted tentiform leafminer, diamondback moth, house fly, stable fly, head lice, and tobacco budworm. Many of these species are resistant to more than one pyrethroid. And, since particulates are easily airborne, they travel , often great distances, from the actual point of application. In both, it can lead to the abnormal growth of breast tissue, leading to development of breasts in males and cancerous breast tissue in both male and females. There is evidence that pyrethroids harm the thyroid gland.
Laboratory tests suggest that permethrin is more acutely toxic to children than to adults.
A known carcinogen. In laboratory tests, xylenes have caused kidney damage, fetal loss, and skeletal anomalies in offspring. It is also a severe fire hazard. The alternative depends on what you are trying to do. In the home, there are a wide range of non-toxic alternatives depending on what type of pest you are trying to control.