is flea collar safe?

Flea collars smell strange, even if it doesn't smell strong to you it may be upsetting your cat. I don't think its anything to worry about though. My cats have new flea collars every 3 months and although they are uncomfortable with them for a day or 2, they soon get used to them.

Flea collars are not good to use. I've seen cats that have lost their hair on their neck and head from them, and one that suffered a chemical burn from it.
I would suggest removing it asap and throwing it away, or if put it in your vacuum cleaner bag to kill any fleas you vacuum up. And, they don't work to keep the fleas off the cats.

Frontline and Advantage work well, or if you want to go the herbal route, try some diatomaceous earth.

You also need to treat your house and your yard if it's an indoor/outdoor cat. Otherwise, the fleas will just return.

Flea collars do have lots of harsh chemicals on them. But most of all I would have to say in my experience the dont work very well. often the fleas jump off and then wait to jump onto you or other pets either. Try another method (i know this would be the most effective but it is the hardest depending on your cats personality) such as bathing the cat. I've noticed that if you use a good flea shampoo most of the fleas are killed and you would be rinsing most of the chemicals off of the cat when you are done. If that is not a possibility try using some of the flea treatments that you place between the shoulder blades on the cat (it is like an oil), frontline has worked the best for me. I did however bathe the cat (boy she put up a fight) then i put on the frontline and i never saw a flea again (i do however continue to use the correct dosage as a preventative measure this is best especially if your cat goes outside). I hope this helps. Oh and will the collar kill the cat no not at all...i just dont like them because my cats tend to get them off, dont like the smell or feel of them etc...