I dove that area a lot back in the lates 70s as well. I never technically cave dived, but lots of spring diving where you were under ledges and could even come up in air pockets to talk with your buddy. But you could always see the light of the entrance. Not really much more dangerous than open water diving, but all diving deserves respect for your equipment, air, dive time, and the ability to know safe limits. When I read 137 feet down, if that’s distance into a spring, it’s not so much. If that’s vertical, that’s a lot and pushes the limits of straight O2 diving.
Maybe they got ‘The Bends’...................