I had no idea something so toxic could be on the market

I sent my husband to the pet store today for some flea stuff for the dogs and cat, he picked up sentry pro. It looked like all the others, he just grabbed it in a hurry. We washed all our pets and put the product on. The whole bottle was supposed to be used for an animal of 60 or more pounds so we just put a tiny bit, maybe 1/8 on the cat, that’s about 1/2 of a teaspoon, maybe even less. We both looked at the box for directions etc. We didn’t see anything that stood out to us as Danger Danger this is poison. This was this morning. At about 10 pm we noticed that the cat was shaking and had goop in his eye. All I could think was maybe I didn’t dry him off enough. I felt horrible. I held him close to me with a blanket for about an hour. After a little bit I thought he was getting better because only his head was shaking and then I noticed it wasn’t really a shaking it was more of a convulsing. My cat looked like he was tripping out. I started to google and nothing was making sense. I say him eat, he hasn’t been sick and then I thought what if it was the flea medicine… I went and got the box. In the tiniest writing on the back it says that this product is fatal to cats. I was shocked. I AM shocked! How can this item be on the market?! And why is there not a GIANT warning sign that this is fatal to cats?! It was small enough that neither my husband or I noticed it when reading the directions. We ussually get frontline and that can be used on both. I had no idea and I feel horrible. Worse yet there is no information on what to do if the cat does get to it! I immediately washed my cat with warm water and soap, and held him for a long while looking on the internet to see what to do because at this point it’s 11 pm and the vet is obviously not available. He then had a seizure and I thought for sure that this was it. Luckily he has gotten better though and seems like he will recover fine. No reactions with the dogs, but I am watching all my pets like a hawk. 3 hours later and my cat is purring and interacting normally, but he’s got almost like a twitch. It’s going to be a long night. I am so sorry to my animals for not reading the fine print. I feel horrible. I am angry that such a product is out there and sad that what I thought to be a good thing at the time (getting rid of the fleas) put them in such distress. I am so sorry for those of you that have lost pets to this horrible product.