diff --git a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/CurvedPatRec.h b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/CurvedPatRec.h
index dd8d3bf91bd2aaa163e91eaec0fd422a9a147954..422f9a629c7dfd2baa2e873219c50f64cbea6743 100644
--- a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/CurvedPatRec.h
+++ b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/CurvedPatRec.h
@@ -2,17 +2,6 @@
   Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
-//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-// 05.04.2008, AUTHOR: OLIVER KORTNER
-// Modified: 25.07.2008 by O. Kortner, improved pattern recognition by using
-//                                     the class "CurvedCandidateFinder".
-//           04.08.2008 by O. Kortner, further improvements of the pattern
-//                                     recognition for large incidence angles.
-//           07.08.2008 by O. Kortner, bug fig in the pattern recognition.
-//           18.08.2008 by O. Kortner, update of chi^2 and segment position
-//                                     and direction added.
-//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-
 #ifndef MuonCalib_CurvedPatRecH
 #define MuonCalib_CurvedPatRecH
 
@@ -31,26 +20,20 @@
 ///
 /// \date 18.08.2008
 
-//::::::::::::::::::
-//:: HEADER FILES ::
-//::::::::::::::::::
+#include "MdtCalibInterfaces/IMdtPatRecFitter.h"
 
 #include "GeoPrimitives/GeoPrimitives.h"
-
-// STL //
-#include <vector>
-
-// MuonCalib //
-#include "MdtCalibInterfaces/IMdtPatRecFitter.h"
 #include "MuonCalibEventBase/MuonCalibSegment.h"
 #include "MdtCalibFitters/MTStraightLine.h"
 #include "MdtCalibFitters/StraightPatRec.h"
 #include "MdtCalibFitters/CurvedLine.h"
+#include "CxxUtils/checker_macros.h"
 
+#include <vector>
 
 namespace MuonCalib {
 
-class CurvedPatRec : public IMdtPatRecFitter {
+class ATLAS_NOT_THREAD_SAFE CurvedPatRec : public IMdtPatRecFitter {
 
 public:
 // Constructors //
diff --git a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/QuasianalyticLineReconstruction.h b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/QuasianalyticLineReconstruction.h
index 30562bcca4dfa1a1b3d72ab076818b7cb29ab208..660ff17cb9028188f5c0cc4adcd983b2b6d94871 100644
--- a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/QuasianalyticLineReconstruction.h
+++ b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/QuasianalyticLineReconstruction.h
@@ -2,28 +2,6 @@
   Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
-//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-// 01.03.2006, AUTHOR: OLIVER KORTNER
-// Modified: 15.07.2006 by O. Kortner, error calculation corrected,
-//                                     chi^2 refit functionality added.
-//           13.01.2007 by O. Kortner, bug fix in candidate treatment, some
-//                                     candidates were considered to be
-//                                     identical although different;
-//                                     modifications to improve the
-//                                     reconstruction efficiency at very high
-//                                     background count rates.
-//           27.03.2007 by O. Kortner, distances with signs filled into
-//                                     MuonCalibSegment.
-//           23.03.2007 by O. Kortner, isnan check for chi^2.
-//           08.06.2007 by O. Kortner, final track segment has rphi position and
-//                                     direction of the initial segment.
-//           23.06.2006 by O. Kortner, add convention for rphi track if the
-//                                     pattern recognition has failed to
-//                                     provide it.
-//           26.11.2007 by O. Kortner, fix for segment refinement.
-//           13.12.2007 by O. Kortner, time-out added.
-//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-
 #ifndef QuasianalyticLineReconstructionH
 #define QuasianalyticLineReconstructionH
 
@@ -46,27 +24,19 @@
 ///
 /// \date 01.03.2006, 16.07.2006, 13.12.2007
 
-//::::::::::::::::::
-//:: HEADER FILES ::
-//::::::::::::::::::
-
-// CLHEP //
-//#include "CLHEP/config/CLHEP.h"
-
-// STL //
-#include <vector>
-
-// MuonCalib //
 #include "MdtCalibInterfaces/IMdtPatRecFitter.h"
+
 #include "MuonCalibEventBase/MuonCalibSegment.h"
 #include "MdtCalibFitters/MTStraightLine.h"
 #include "MdtCalibFitters/IndexSet.h"
 #include "MdtCalibFitters/DCSLFitter.h"
+#include "CxxUtils/checker_macros.h"
 
+#include <vector>
 
 namespace MuonCalib {
 
-class QuasianalyticLineReconstruction : public IMdtPatRecFitter {
+class ATLAS_NOT_THREAD_SAFE QuasianalyticLineReconstruction : public IMdtPatRecFitter {
 
 public:
 // Constructors //
diff --git a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/StraightPatRec.h b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/StraightPatRec.h
index fe3c9631c08f205068f3abf10894ec80c0ae8de9..36774fcec18c5810df912b6ab685df5ca5ffb912 100644
--- a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/StraightPatRec.h
+++ b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/MdtCalibFitters/StraightPatRec.h
@@ -2,16 +2,6 @@
   Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
-//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-// 27.10.2007, AUTHOR: OLIVER KORTNER
-// Modified: 26.11.2007 by O. Kortner, fix for segment refinement.
-//           13.12.2007 by O. Kortner, time-out added.
-//           07.08.2008 by O. Kortner, bug fix when hits are disabled.
-//				 19.11.2008 by I. Potrap: 1) several bugs have been fixed;
-//												  2) external fitter(DCLS) replaced by
-//													  internal code of linear-least-chi2-fit
-//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-
 #ifndef StraightPatRecH
 #define StraightPatRecH
 
@@ -29,30 +19,19 @@
 ///
 /// \date 27.10.2007, 13.12.2007
 
-//::::::::::::::::::
-//:: HEADER FILES ::
-//::::::::::::::::::
+#include "MdtCalibInterfaces/IMdtPatRecFitter.h"
 
-// CLHEP //
-//#include "CLHEP/config/CLHEP.h"
-//#include "CLHEP/Units/SystemOfUnits.h"
-//#include "CLHEP/Units/PhysicalConstants.h"
 #include "GeoPrimitives/GeoPrimitives.h"
-
-// STL //
-#include <vector>
-
-// MuonCalib //
-#include "MdtCalibInterfaces/IMdtPatRecFitter.h"
 #include "MuonCalibEventBase/MuonCalibSegment.h"
 #include "MdtCalibFitters/MTStraightLine.h"
 #include "MdtCalibFitters/DCSLFitter.h"
-//#include "MdtCalibFitters/FourCasesFitter.h"
+#include "CxxUtils/checker_macros.h"
 
+#include <vector>
 
 namespace MuonCalib {
 
-class StraightPatRec : public IMdtPatRecFitter {
+class ATLAS_NOT_THREAD_SAFE StraightPatRec : public IMdtPatRecFitter {
 
 public:
 // Constructors //
diff --git a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/src/StraightPatRec.cxx b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/src/StraightPatRec.cxx
index b57343fc75cbdd69c4f246f3ed1f5b87120dac82..1a098af59e8496c60ff96b3146e733972e134e7c 100644
--- a/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/src/StraightPatRec.cxx
+++ b/MuonSpectrometer/MuonCalib/MdtCalib/MdtCalibFitters/src/StraightPatRec.cxx
@@ -411,7 +411,7 @@ double StraightPatRec::chi2(void) const {
 //:: METHOD chi2PerDegreesOfFreedom ::
 //::::::::::::::::::::::::::::::::::::
 
-double StraightPatRec::chi2PerDegreesOfFreedom(void) const{
+double StraightPatRec::chi2PerDegreesOfFreedom(void) const {
 
 	if (m_nb_track_hits<3) {
 		return -1;
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/EventHandler.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/EventHandler.h
index 5995db2073a7a4e36166745c304cc27c82a310ba..e26823ba3ee19148336b073623f35bf7c09211bb 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/EventHandler.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/EventHandler.h
@@ -1,15 +1,17 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef EventHandler_h
 #define EventHandler_h
 
-#include <vector>
-#include <string>
-#include <map>
 #include "MuonCalibExtraTreeEvent/MuonCalibExtendedRawHits.h"
- 
+#include "CxxUtils/checker_macros.h"
+
+#include <map>
+#include <string>
+#include <vector>
+
 namespace MuonCalib{
 
   class MuonCalibExtendedTrack;
@@ -19,7 +21,7 @@ namespace MuonCalib{
   /**
      @author Niels.van.eldik@cern.ch
   */
-  class EventHandler {
+  class ATLAS_NOT_THREAD_SAFE EventHandler {
 
   public:
     struct AuthorIndices {
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedRawHits.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedRawHits.h
index ee7cddcfa16fc0fdd2f349b7b2d012501cef138e..b2baf28439cde0f9ad2f4ec4108a325ef11e6dfe 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedRawHits.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedRawHits.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONCALIBEXTENDEDRAWHITS_H
@@ -8,7 +8,7 @@
 #include "MuonCalibIdentifier/MuonFixedId.h"
 #include "MuonCalibExtraUtils/MuonFixedIdManipulator.h"
 #include "MuonCalibExtraUtils/MuonCalibLayerMapping.h"
-
+#include "CxxUtils/checker_macros.h"
 
 namespace MuonCalib {
   
@@ -29,7 +29,7 @@ namespace MuonCalib {
 
      @author niels.van.eldik@cern.ch
   */
-  class MuonCalibExtendedRawHits {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibExtendedRawHits {
   public:
     struct ExtendedChannelInfo {
       std::vector<const MuonCalibRawMdtHit*>       hits;
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedSegment.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedSegment.h
index 0f337925c9e135eec1df6e0772f1a17a38fea87f..c2958702910b1c1ed493f704f0ea7426313c43ba 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedSegment.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedSegment.h
@@ -1,16 +1,17 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONCALIBEXTENDEDSEGMENT_H
 #define MUONCALIBEXTENDEDSEGMENT_H
 
 #include "MuonCalibEventBase/MuonCalibSegment.h"
+
 #include "MuonCalibExtraTreeEvent/MuonCalibTrackSummary.h"
 #include "MuonCalibExtraUtils/MuonCalibLayerMapping.h"
 #include "MuonCalibEventBase/MuonCalibSegment.h"
 #include "MuonCalibExtraTreeEvent/MuonCalibRawHitAssociationMap.h"
-
+#include "CxxUtils/checker_macros.h"
 
 #include <vector>
 #include <map>
@@ -27,7 +28,7 @@ namespace MuonCalib {
 
      @author niels.van.eldik@cern.ch
   */
-  class MuonCalibExtendedSegment : public MuonCalibSegment {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibExtendedSegment : public MuonCalibSegment {
   public:
     /**  Constructor taking input track. */
     MuonCalibExtendedSegment( const MuonCalibSegment& segment );
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedTrack.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedTrack.h
index 1ab0d47880c5fd62a7de34697ef1c9c41b2f5b7b..40c2c501cafa98264f4077d3b04cd6867d0570e1 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedTrack.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibExtendedTrack.h
@@ -14,8 +14,10 @@
 #include "GaudiKernel/MsgStream.h"
 #include "AthenaKernel/getMessageSvc.h"
 #include "GeoPrimitives/GeoPrimitives.h"
+#include "CxxUtils/checker_macros.h"
 
 #include <string>
+#include <vector>
 #include <algorithm>
 
 namespace MuonCalib {
@@ -30,7 +32,7 @@ namespace MuonCalib {
 
      @author niels.van.eldik@cern.ch
   */
-  class MuonCalibExtendedTrack : public MuonCalibTrack_E {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibExtendedTrack : public MuonCalibTrack_E {
   public:
     /**  Constructor taking input track. */
     MuonCalibExtendedTrack( const MuonCalibTrack_E& track, int pdgCode = 0, int barCode = 0 );
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibRawHitAssociationMap.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibRawHitAssociationMap.h
index 3dc5e7f12240c56ae1bf1473f8fb095ccec63835..545a6d115539d67eb4c362224c3a24e9c2cf6c2d 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibRawHitAssociationMap.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibRawHitAssociationMap.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONCALIBRAWHITASSICATIONMAP_H
@@ -9,6 +9,7 @@
 #include "MuonCalibEventBase/MuonCalibRawRpcHit.h"
 #include "MuonCalibEventBase/MuonCalibRawTgcHit.h"
 #include "MuonCalibEventBase/MuonCalibRawCscHit.h"
+#include "CxxUtils/checker_macros.h"
 
 #include <map>
 
@@ -21,7 +22,7 @@ namespace MuonCalib {
 
      @author niels.van.eldik@cern.ch
   */
-  class MuonCalibRawHitAssociationMap  {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibRawHitAssociationMap  {
   public:
     /** get raw csc hit for given Identifier, returns 0 if not on track */
     const MuonCalibRawCscHit* getRawCscHit( const MuonFixedId& id ) const;
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibSelector.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibSelector.h
index 342d2aea10ad83f9fe1f15c6a1b38d4d1a0621e1..21c4256c0c31ff5fe91fdf4a0e6c48de13e5b406 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibSelector.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibSelector.h
@@ -1,10 +1,12 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONCALIBEXTRANTUPLEANALYSIS_MUONCALIBSELECTOR_H
 #define MUONCALIBEXTRANTUPLEANALYSIS_MUONCALIBSELECTOR_H
 
+#include "CxxUtils/checker_macros.h"
+
 #include <vector>
 
 namespace MuonCalib {
@@ -13,7 +15,7 @@ namespace MuonCalib {
   class MuonCalibExtendedTrack;
   class MuonCalibTrackSummary;
 
-  class MuonCalibSelector {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibSelector {
   public: 
     typedef std::vector<const MuonCalibExtendedSegment*> SegVec;
     typedef SegVec::iterator                             SegIt;
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTrackSummary.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTrackSummary.h
index 8372eda9ec1df0730afc55da605c305341dfb89d..84231d6969112002d91e0b57e1a17ae46005e966 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTrackSummary.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTrackSummary.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONCALIBTRACKSUMMARY_H
@@ -7,13 +7,15 @@
 
 #include "MuonCalibIdentifier/MuonFixedId.h"
 #include "MuonCalibExtraUtils/MuonFixedIdManipulator.h"
+#include "CxxUtils/checker_macros.h"
+
 #include <string>
 #include <vector>
 #include <set>
 
 namespace MuonCalib {
 
-  class MuonCalibTrackSummary {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibTrackSummary {
   public:
 
     struct ChamberHitSummary {
@@ -31,24 +33,24 @@ namespace MuonCalib {
       MuonFixedId chId;
       bool isMdt() const { return chId.is_mdt(); }
 
-      int nhits() const     { return m_first.nhits + m_second.nhits; }
-      int nholes() const    { return m_first.nholes + m_second.nholes; }
-      int noutliers() const { return m_first.noutliers + m_second.noutliers; }
-      int ndeltas() const   { return m_first.ndeltas + m_second.ndeltas; }
+      int nhits ATLAS_NOT_THREAD_SAFE () const     { return m_first.nhits + m_second.nhits; }
+      int nholes ATLAS_NOT_THREAD_SAFE () const    { return m_first.nholes + m_second.nholes; }
+      int noutliers ATLAS_NOT_THREAD_SAFE () const { return m_first.noutliers + m_second.noutliers; }
+      int ndeltas ATLAS_NOT_THREAD_SAFE () const   { return m_first.ndeltas + m_second.ndeltas; }
 
-      int netaHits() const { return isMdt() ? nhits() : m_first.nhits; }
-      int nphiHits() const { return isMdt() ? 0       : m_second.nhits; }
+      int netaHits ATLAS_NOT_THREAD_SAFE () const { return isMdt() ? nhits() : m_first.nhits; }
+      int nphiHits ATLAS_NOT_THREAD_SAFE () const { return isMdt() ? 0       : m_second.nhits; }
 
-      int nMdtHitsMl1() const { return isMdt() ? m_first.nhits  : 0; }
-      int nMdtHitsMl2() const { return isMdt() ? m_second.nhits : 0; }
+      int nMdtHitsMl1 ATLAS_NOT_THREAD_SAFE () const { return isMdt() ? m_first.nhits  : 0; }
+      int nMdtHitsMl2 ATLAS_NOT_THREAD_SAFE () const { return isMdt() ? m_second.nhits : 0; }
 
       // before using make sure isMdt == true!
-      Projection& mdtMl1() const { return m_first; }
-      Projection& mdtMl2() const { return m_second; }
+      Projection& mdtMl1 ATLAS_NOT_THREAD_SAFE () const { return m_first; }
+      Projection& mdtMl2 ATLAS_NOT_THREAD_SAFE () const { return m_second; }
 
       // before using make sure isMdt == false!
-      Projection& etaProjection() const { return m_first; }
-      Projection& phiProjection() const { return m_second; }
+      Projection& etaProjection ATLAS_NOT_THREAD_SAFE () const { return m_first; }
+      Projection& phiProjection ATLAS_NOT_THREAD_SAFE () const { return m_second; }
       
 
       private:
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTriggerInfo.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTriggerInfo.h
index 82b9874c260b6bab0378b2c5606356c88a8ed09c..daa2aaaf55ebddcbd8178eb45b5316e4f5532ff1 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTriggerInfo.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraTreeEvent/MuonCalibExtraTreeEvent/MuonCalibTriggerInfo.h
@@ -1,10 +1,12 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef MUONCALIBTRIGGERINFO_H
 #define MUONCALIBTRIGGERINFO_H
 
+#include "CxxUtils/checker_macros.h"
+
 #include <string>
 #include <vector>
 
@@ -29,7 +31,7 @@ namespace MuonCalib{
   };
 
   /** helper class to for MuonCalibTriggerType which provides a mapping to the actual bit number */
-  class MuonCalibTriggerTypeHelper {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibTriggerTypeHelper {
   public:
     /** get trigger bit for a given type */
     static std::vector<int> triggerBits( MuonCalibTriggerType type );
@@ -69,7 +71,7 @@ namespace MuonCalib{
      
      @author Niels van Eldik
   */
-  class MuonCalibTriggerInfo{
+  class ATLAS_NOT_THREAD_SAFE MuonCalibTriggerInfo{
   public:
     MuonCalibTriggerInfo();                                                                               //!< default constructor
     MuonCalibTriggerInfo( MuonCalibTriggerType type, double bcOffset );
diff --git a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraUtils/MuonCalibExtraUtils/MuonCalibSimpleHoleSearch.h b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraUtils/MuonCalibExtraUtils/MuonCalibSimpleHoleSearch.h
index 3c4d9fb3effbff14cf28f0d943d260a5463d9b94..9279b8946a47abc6616fe165a8a34d04cdab455f 100644
--- a/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraUtils/MuonCalibExtraUtils/MuonCalibSimpleHoleSearch.h
+++ b/MuonSpectrometer/MuonCalib/MuonCalibExtraTree/MuonCalibExtraUtils/MuonCalibExtraUtils/MuonCalibSimpleHoleSearch.h
@@ -10,14 +10,14 @@
 #include "MuonCalibExtraUtils/MuonFixedIdManipulator.h"
 #include "MuonCalibIdentifier/MuonFixedId.h"
 #include "GeoPrimitives/GeoPrimitives.h"
-
+#include "CxxUtils/checker_macros.h"
 
 #include <vector>
 
 namespace MuonCalib {
 
 
-  class MuonCalibSimpleHoleSearch {
+  class ATLAS_NOT_THREAD_SAFE MuonCalibSimpleHoleSearch {
   public:
     struct Result {
       Result() {}