diff --git a/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/ATLAS_CHECK_THREAD_SAFETY b/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/ATLAS_CHECK_THREAD_SAFETY
new file mode 100644
index 0000000000000000000000000000000000000000..43fe75649c6dc0f8b2b0c4bdbde8aae7cbef02f5
--- /dev/null
+++ b/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/ATLAS_CHECK_THREAD_SAFETY
@@ -0,0 +1 @@
+PhysicsAnalysis/TruthParticleID/McParticleEvent
diff --git a/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthEtIsolations.h b/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthEtIsolations.h
index dfd6c00c4d9f24e3332b2b34e212419fe0994037..2afec5280e4b85b4a853261bd1fed116c8ac8f52 100644
--- a/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthEtIsolations.h
+++ b/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthEtIsolations.h
@@ -1,7 +1,7 @@
 ///////////////////////// -*- C++ -*- /////////////////////////////
 
 /*
-  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 */
 
 // TruthEtIsolations.h 
@@ -210,7 +210,7 @@ class TruthEtIsolations
   /// The default Et isolation energy which is being returned when
   /// I don't know what to return.
   /// That's ugly but for backward compatibility's sake... Next EDM :P
-  static EtIsol_t m_dfltEtIsols;
+  static const EtIsol_t m_dfltEtIsols;
 }; 
 
 /////////////////////////////////////////////////////////////////// 
diff --git a/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthParticleParamDefs.h b/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthParticleParamDefs.h
index 7d07ac4884fd2087bff73e4e3ae5fcc206d6b48d..9d01b0f0d7ac003c9107754ddc3be04c80f86bb5 100644
--- a/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthParticleParamDefs.h
+++ b/PhysicsAnalysis/TruthParticleID/McParticleEvent/McParticleEvent/TruthParticleParamDefs.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////// 
@@ -36,7 +36,7 @@ namespace TruthParticleParameters {
   /// The actual definition of delta R cuts for each cone
   inline
   double coneCut( const TruthParticleParameters::ConeSize idx ) {
-    static ConeCuts_t coneCuts = { 
+    static const ConeCuts_t coneCuts = { 
       {
 	0.10, // TruthParticleParameters::etcone10
 	0.20, // TruthParticleParameters::etcone20
diff --git a/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthEtIsolations.cxx b/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthEtIsolations.cxx
index a6d1a6471d0ba69f59174d1fdff356a3e943ade5..16bf2cca0059ac015f610ebd68d361f2506d242f 100644
--- a/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthEtIsolations.cxx
+++ b/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthEtIsolations.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////// 
@@ -28,7 +28,7 @@
 typedef TruthEtIsolations::GenEventLink_t GenEventLink_t;
 typedef TruthEtIsolations::EtIsol_t       EtIsol_t;
 
-EtIsol_t TruthEtIsolations::m_dfltEtIsols = {
+const EtIsol_t TruthEtIsolations::m_dfltEtIsols = {
   {
     -999.*CLHEP::GeV, -999.*CLHEP::GeV, -999.*CLHEP::GeV, -999.*CLHEP::GeV,
     -999.*CLHEP::GeV, -999.*CLHEP::GeV, -999.*CLHEP::GeV, -999.*CLHEP::GeV
diff --git a/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthParticleBase.cxx b/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthParticleBase.cxx
index 9c0a24f46a754c79faf7aede4bbd3bfc2d1e988d..c3cacf281ccdf4b76cdbe8a7a1fd7c14579cc72c 100644
--- a/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthParticleBase.cxx
+++ b/PhysicsAnalysis/TruthParticleID/McParticleEvent/src/TruthParticleBase.cxx
@@ -1,7 +1,7 @@
 ///////////////////////// -*- C++ -*- /////////////////////////////
 
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 */
 
 // TruthParticleBase.cxx 
@@ -75,7 +75,7 @@ TruthParticleBase::origin() const
 const ElementLink<VxContainer>& 
 TruthParticleBase::originLink() const
 {
-  static ElementLink<VxContainer> origin;
+  static const ElementLink<VxContainer> origin;
   return origin;
 }