Orangeburg pipe was simply a good idea (make a wastepipe cheaper & lighter than clay or cast iron) that suffered from a bad solution (using a tar/oil impregnated fiber based pipe). It strikes me as odd that this solution was promulgated in the 60’s and 70’s, since by then the plastics industry had better alternatives. Polyethylene would have been a better choice, even ABS or PVC. If you have a sewer done in Orangeburg, it will definitely need replacement, as their expected life-expectancy has been exceeded by now.
NtP