- as of 12:51 the CBOE and C2 are reopened and available for trading

And promptly, BATS "self-helps" itself against OPRA:
- BATS TO HALT OPTIONS TRADING FROM 1:30 PM UNTIL OPRA RESTORED
- BATS OPTIONS HALTS TRADING AT 1:30PM ON OPRA ISSUE
And now Nasdaq:

Finally, IB chimes in:
- Due to OPRA data dissemination issues all US OPTIONS trading venues have halted trading.
http://www.zerohedge.com/news/2013-09-16/another-day-another-exchange-breaks