According to the
Connecticut Department of Public Health, permethrin "has low mammalian toxicity, is poorly absorbed through the skin and is rapidly inactivated by the body. Skin reactions have been uncommon."[SUP]
[8][/SUP]
Excessive exposure to permethrin can cause
nausea, headache, muscle weakness, excessive
salivation, shortness of breath, and
seizures. Worker exposure to the chemical can be monitored by measurement of the
urinary metabolites, while severe
overdosage may be confirmed by measurement of permethrin in
serum or
blood plasma.[SUP]
[9][/SUP]
Permethrin does not present any notable
genotoxicity or
immunotoxicity in humans and farm animals, but is classified by the
United States Environmental Protection Agency (EPA) as a likely human
carcinogen, based on reproducible studies in which mice fed permethrin developed liver and lung
tumors.[SUP]
[10][/SUP] Carcinogenic action in
nasal mucosal cells due to
inhalation exposure is suspected, due to observed genotoxicity in human tissue samples, and in rat livers the evidence of increased
pre-neoplastic lesions raises concern over
oral exposure.[SUP]
[11][/SUP][SUP]
[12][/SUP]
Studies by Bloomquist et al., 2002 [SUP]
[13][/SUP] suggested a link of permethrin exposure to
Parkinson's disease, including very small (per kg.) exposures:
2002 study - "Our studies have documented low-dose effects of permethrin, doses below one-one thousandth of a
lethal dose for a mouse, with effects on those
brain pathways [that are] involved in Parkinson's Disease [...] We have found effects consistent with a pre-parkinsonsian condition, but not yet full-blown
parkinsonism." [SUP]
[14][/SUP][SUP]
[15][/SUP]However a more recent 2007 study by the same researcher concluded that there was "little hazard to humans"
