As of last check it is permethrin:
Permethrin Pyrethroid insecticide and neurotoxin.[36] Permethrin is classified as a carcinogen by EPA because it causes lung and liver tumors in mice. Furthermore, the insecticide is hazardously toxic to honey bees and other beneficial insects, fish, aquatic insects, crayfish and shrimp.[37] In part because of its extreme aqua-toxicity, permethrin is an EPA restricted-use pesticide.[38] http://www.panna.org/campaigns/caia/corpProfilesBASF.dv.html
Permethrin is a Pyrethroid compound. Report a Poisoning
Symptoms of Poisoning with Pyrethroid Compounds Find Products Containing this Chemical
- Irritation of skin and eyes.
- Irritability to sound or touch, abnormal facial sensation, sensation of prickling, tingling or creeping on skin, numbness.
- Headache, dizziness, nausea, vomiting, diarrhea, excessive salivation, fatigue.
- In severe cases: fluid in the lungs and muscle twitching may develop. Seizures may occur and are more common with more toxic cyano-pyrethroids.
Acute Toxicity 2
WHO Acute Hazard
TRI Acute Hazard
Material Safety Data Sheets
Acute rating from U.S. EPA product label
U.S. NTP Acute Toxicity Studies
View Studies
Cholinesterase Inhibitor II, Moderately Hazardous
Endocrine Disruption
Illinois EPA list Suspected
Keith list Not Listed
Colborn list Yes
Benbrook list Yes
EU list
http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35397
The insecticide permethrin (in the synthetic pyrethroid family) is widely used on cotton, wheat, corn, alfalfa, and other crops. In addition, over 100 million applications are made annually in and around U.S. homes.
Permethrin, like all synthetic pyrethroids, is a neurotoxin. Symptoms include tremors, incoordination, elevated body temperature, increased aggressive behavior, and disruption of learning. Laboratory tests suggest that permethrin is more acutely toxic to children than to adults.
The U.S. Environmental Protection Agency has classified permethrin as a carcinogen because it causes lung tumors in female mice and liver tumors in mice of both sexes. Permethrin inhibits the activity of the immune system in laboratory tests, and also binds to the receptors for a male sex hormone. It causes chromosome aberrations in human and hamster cells.
Permethrin is toxic to honey bees and other beneficial insects, fish, aquatic insects, crayfish, and shrimp. For many species, concentrations of less than one part per billion are lethal. Permethrin causes deformities and other developmental problems in tadpoles, and reduces the number of oxygen-carrying cells in the blood of birds.
Permethrin has been found in streams and rivers throughout the United States. It is also routinely found on produce, particularly spinach, tomatoes, celery, lettuce, and peaches.
A wide variety of insects have developed resistance to permethrin. High levels of resistance have been documented in cockroaches, head lice, and tobacco budworm. http://www.safe2use.com/poisons-pesticides/pesticides/permethrin/cox-report/cox.htm
There's plenty more info on this one.
SJ - yes, technically you are right, but unless spraying is banned, which it never will be, what you are hoping for will not be realized (no poisions at all). Minimizing your exposure is the best you can do for yourself. Will putting a No Spray sign minimize your risk of developing cancer due to exposure of the poison? Who knows? 
With all the poisons and toxins in our environment today, who the heck knows what ultimately causes cancer - no way we could pinpoint it and maybe why we don't hear of lawsuits against the County Mosquito Control Department. 
