Also look under Technical Notice for April 28, it is loaded with all the issues today. http://www.finra.org/
U3 Trading Halt explained; Halt – Extraordinary Events Trading is halted because NASD has determined that an extraordinary event has occurred or is ongoing that has had a material effect on the market for the OTC Equity Security or has caused or has the potential to cause major disruption to the marketplace and/or significant uncertainty in the settlement and clearance process.