From my understanding,... & this could be wrong (please correct me if I am), a lot of these accidents occur from divers that are not prepared for diving in deep & very cold waters of some of the quarries of the region. Gilboa is one of them. Although some of the accidents are medical related or somehing else, many of them are divers that likely experience regulator freeze- ups & freeflows at depth, freak out & then bolt to the surface. I have never dove this particular quarry, but frequently dive another that is very similar in KY. I have had a freeze- up & free flow myself (breathed off the regulator until I reached the surface) & have had to assist a buddy who had it happen to him. I had to slow his ascent when he panicked & bolted. Any more,.... I never go deep without wearing redundant air supplies (double cylinders & a bail- out bottle). I also teach my students how to breathe off a free flowing regulator, also telling them that if they dive the local quarries enough, it is a matter of not "if" it will happen, but "when" it will. If you plan to dive in these environments, get some training &/ or mentoring to do it safely & carry a redundant air supply with you,.... just in case. These colder waters can be dived in safely, but can not be taken lightly or for granted.
Tammy, good point on the free flow regs. Your information is largely what I have heard. My Instructor buds say the "deep" side is very cold/dark. I have dived Gilboa 20-25 times and always in the "shallow" end. I have a lot of respect for the deep side and when I do attempt it, I will be accompanied by VERY experienced parties and bring redundant air.