This highly controversial pesticide is one of the early submissions made to the EPA using the probabilistic risk assessment approach. 

See what was submitted by American Cyanamid and what the EPA had to say about it HERE.

There is also a Scientific American article on this compound that is worth checking out. 

Kelley Tucker of the American Bird Conservancy's pesticide campaign has been active in questioning the registration of this chemical.  Visit her site to see the time line of actions their group has taken on this pesticide.