I found it in the archives. Here it is: > WASHlNGTON - East Coast and West Coast, the pattern has been the > same: At about 11 a.m., an entire region's telephone system collapses. > For the past six days, solving the mystery of the failing phones has > become an obsession for the nation's service-conscious telephone > companies. Yet despite recurring similarities and clues in the > half-dozen failures to date, which have struck Washington, Los > Angeles, Pittsburgh and San Francisco. the detective work remains > mired in unanswered questions.
This was the subsequent problem on the AT&T network that affected only some 4ESS tandems in June 1991.
Here's an article you can read about all the "known" crashes in the early 1990s, including the one mentioned above:
Dave Perrussel Webmaster - Telephone World