@@ -474,6 +474,9 @@ API changes
     instantiated).  As unit formatters are mostly an internal implementation
     detail this is not likely to affect any users. [#4001]
 
+  - CGS E&M units are now defined separately from SI E&M units, and have
+    distinct physical types. [#4255]
+
 - ``astropy.utils``
 
   - All of the ``get_pkg_data_*`` functions take an optional ``package``
 
@@ -114,7 +114,7 @@
 ###########################################################################
 # BASES
 
-bases = set([cm, g, s, C, rad, cd, K, mol])
+bases = set([cm, g, s, rad, cd, K, mol])
 
 
 ###########################################################################
 
@@ -124,6 +124,10 @@ def get_physical_type(unit):
     (astrophys.photon / si.AA / si.cm ** 2 / si.s, 'photon flux density wav'),
     (astrophys.R, 'photon flux'),
     (astrophys.bit, 'data quantity'),
-    (astrophys.bit / si.s, 'bandwidth')
+    (astrophys.bit / si.s, 'bandwidth'),
+    (cgs.Franklin, 'electrical charge (ESU)'),
+    (cgs.statampere, 'electrical current (ESU)'),
+    (cgs.Biot, 'electrical current (EMU)'),
+    (cgs.abcoulomb, 'electrical charge (EMU)')
 ]:
     def_physical_type(unit, name)