Can a court order allowing a parent unsupervised visitation be ignored if the child's safety is at risk?

No. Do not ignore the Order. By not complying with an order, you will put yourself at risk of a contempt finding-this can result in up to six months incarceration. I agree with my colleague above. If the child is in imminent danger to his/her life of health the best thing to do is file a petition in court to modify the old order. Make sure that you are detailed in your description of why the child is at risk, and how you know.    

You shuld never ignore a court order but more improtantly, you should never put a child's safety at risk.  So if you believe that the child will be at risk if they are permitted unsupervied visitation then you nee to apply to the court immediately for a modification of the visitation agreement and for a tempary stay of the visitation until a hearing can be held.  Now, you need real proof of the safety issue and if you rought this up in the divorce and did not properly prove it and are now looking to do so again, please have really, really good proof or you could put yourself in a bad light and situation with the judge.  It would be considered interference with parental rights for one thing.  Good luck.