A listener in Michigan is reporting he got a Close Call hit and heard P25 Coast Guard communications on 167.6250 MHz, N293. Here is the Radio Reference thread:
http://forums.radioreference.com/marine-monitoring-forum/269338-coast-guard-digital.html#post1993308
Even though I have never heard of that frequency being allocated to Coast Guard operations, it could be a new allocation for a special use channel. Some under-used frequencies, especially near border areas, can be utilized by agencies that you would normally not expect.
Also, some are thinking this might be a special channel for interoperability with the FBI, since it falls in the 167 MHz area that we are used to seeing their communications in. However, many of the frequencies in the 167-168 MHz area are not exclusive allocations to the Justice Department or the FBI, and can be assigned to other agencies. Also, there are plenty of existing federal interoperability channels already in the FBI and Coast Guard radios that are available for use by both agencies.
UPDATE!
Another listener now states that CG Sector Toledo has been using 167.1125 MHz, N293 for some of their operations. The channel has been identified by users as "AG-101".