let me see if I can find more info. I'm copying pieces of what I found when I did my research which again makes me uncomfortable to use it. ETA - this post is not to judge anyone who does use it, but explain why I am uncomfortable using it.
Lastly; Summit Vetpharm LLC, during the time of the EPA’s Public Advisory, was primarily held by Sumitomo Corporation the same company that owns Hartz. Sumitomo transferred it’s primary shares of Summit Vetpharm LLC a little while ago and in May of this year, they will hand over majority stock of Hartz to Unicharm, a large player in the Asian pet-care market. Sumitomo is also the manufacturer of Permethrin, the chemical referenced above.
A class action suit was filed against both companies in 3/2010
Adverse Reactions from Flea Control Products - 2012-02
Hartz Faces Wave of Lawsuits Over Flea Products
Hartz Mountain Corp. is facing a wave of new lawsuits from dog and cat owners claiming that their pets were sickened or killed by anti flea nad tick medication sold by the company. The suit charges Hartz with negligence and with creating an “unreasonably dangerous product.” The products named include Hartz Ultra Guard flea and tick drops and Summit VetPharm’s Vectra 3d. Many of the suits filed are seeking 'class action" status with one suit claiming that “in 2008 alone, there were approximately 48,000 reports of adverse events from the spot-on or squeeze-on products including pyrethrins, Permethrin, or other pyrethroids.” (Read more)
CalgaryVeterinarians.ca : CalgaryVeterinarians.ca