diff --git a/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyMeas.h b/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyMeas.h
index 14e42da918082fc23ce076a5e365513712a28a45..70420ae31177469eb50c0e494db0a3ef80d1808c 100755
--- a/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyMeas.h
+++ b/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyMeas.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
 */
 
 ///////////////////////////////////////////////////////////////////
@@ -25,6 +25,8 @@
 #include "CaloEvent/CaloCellContainer.h"
 #include "CaloConditions/CaloNoise.h"
 
+#include <atomic>
+
 //<<<<<< CLASS DECLARATIONS                                             >>>>>>
 
 class CaloCellContainer;
@@ -108,12 +110,12 @@ private:
     double			m_sigmasAboveNoise;	// The minimum sigmas above the noise tool rms
     double			m_sigmasAboveNoiseCore;	// The minimum sigmas above the noise tool rms
 
-    mutable int			m_totalCoreCellsEM;
-    mutable int			m_totalCoreCellsHEC;
-    mutable int			m_totalCoreCellsTile;
-    mutable int			m_totalSelectedEM;
-    mutable int			m_totalSelectedHEC;
-    mutable int			m_totalSelectedTile;
+    mutable std::atomic_int	m_totalCoreCellsEM;
+    mutable std::atomic_int	m_totalCoreCellsHEC;
+    mutable std::atomic_int	m_totalCoreCellsTile;
+    mutable std::atomic_int	m_totalSelectedEM;
+    mutable std::atomic_int	m_totalSelectedHEC;
+    mutable std::atomic_int	m_totalSelectedTile;
 };
 
 }	// end of namespace
diff --git a/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyTool.h b/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyTool.h
index fc53792d9e6ef9efd8513f68498eaa7e803b2fde..3d8e90298609e2add934968cef8ed74328e1752a 100755
--- a/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyTool.h
+++ b/Reconstruction/MuonIdentification/MuidCaloEnergyTools/MuidCaloEnergyTools/MuidCaloEnergyTool.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
 */
 
 //////////////////////////////////////////////////////////////////////////////
@@ -28,6 +28,8 @@
 #include "GaudiKernel/ToolHandle.h"
 #include "MuidInterfaces/IMuidCaloEnergy.h"
 
+#include <atomic>
+
 //<<<<<< CLASS DECLARATIONS                                             >>>>>>
 
 namespace Rec
@@ -104,9 +106,9 @@ private:
     double					m_minMuonPt;      // minimum pt of the muon
 
     // counters (for finalize)
-    mutable int 				m_countMean;        //number of tracks using mean
-    mutable int					m_countMeasurement; //number of tracks using measurement
-    mutable int 				m_countMop;         //number of tracks using mop
+    mutable std::atomic_int			m_countMean;        //number of tracks using mean
+    mutable std::atomic_int			m_countMeasurement; //number of tracks using measurement
+    mutable std::atomic_int 			m_countMop;         //number of tracks using mop
 };
 
 }	// end of namespace