“I would like to know if we have joint custody of our kids but i feel they are in danger when they are with her do i have the right to say they cant go with her?”
In a word, no. Joint custody means that you share custody either equally, or in some proportion usually more than the more traditional full-time with mother and every other weekend with father.
But it doesn’t mean that you can make unilateral changes to your timeshare schedule, or really to any other status quo.
If you truly feel that your child is in danger while with the other parent, then you should immediately have your lawyer request an emergency change of custody from the court. Any delay will only cause the court to assume that the danger is not that immediate.