diff --git a/include/cantera/kinetics/Kinetics.h b/include/cantera/kinetics/Kinetics.h
index a2190155e..b7dbd2d32 100644
--- a/include/cantera/kinetics/Kinetics.h
+++ b/include/cantera/kinetics/Kinetics.h
@@ -987,10 +987,6 @@ protected:
 
     //! @see skipUndeclaredThirdBodies()
     bool m_skipUndeclaredThirdBodies;
-
-private:
-    std::map<size_t, std::vector<grouplist_t> > m_rgroups;
-    std::map<size_t, std::vector<grouplist_t> > m_pgroups;
 };
 
 }
diff --git a/src/kinetics/Kinetics.cpp b/src/kinetics/Kinetics.cpp
index 2b5a5d6c7..4e0081f00 100644
--- a/src/kinetics/Kinetics.cpp
+++ b/src/kinetics/Kinetics.cpp
@@ -59,8 +59,6 @@ Kinetics& Kinetics::operator=(const Kinetics& right)
     m_surfphase = right.m_surfphase;
     m_rxnphase = right.m_rxnphase;
     m_mindim = right.m_mindim;
-    m_rgroups = right.m_rgroups;
-    m_pgroups = right.m_pgroups;
     m_rfn = right.m_rfn;
     m_rkcn = right.m_rkcn;
     m_ropf = right.m_ropf;