diff --git a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/G4DetectorConstruction.cxx b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/G4DetectorConstruction.cxx
index 64807bc327b7bb695986f69e3d0df0783e727161..a5c8db1a01cbcfdeea166f37cacb7115036bd14e 100644
--- a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/G4DetectorConstruction.cxx
+++ b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/G4DetectorConstruction.cxx
@@ -26,8 +26,13 @@ G4Material* G4DetectorConstruction::s_g4vacuum = new G4Material("Vacuum",1.,1.01
                                                                      kStateGas,0.1*CLHEP::kelvin, 1.e-19*CLHEP::pascal);
 
 G4DetectorConstruction::G4DetectorConstruction()
-  :   m_worldLog(0),
-      m_worldPhys(0)
+  :   m_material(nullptr),
+      m_worldLog(nullptr),
+      m_detectorLog(nullptr),
+      m_layerLog(nullptr),
+      m_worldPhys(nullptr),
+      m_detectorPhys(nullptr),
+      m_layerPhys(nullptr)
 {}
 
 
diff --git a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/PhysicsValidationUserAction.cxx b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/PhysicsValidationUserAction.cxx
index 72ba17deaf256a0a8301d2ab1ad43f57f2665944..e7608fa721fbcf666784bb1b67418dae6e439b31 100644
--- a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/PhysicsValidationUserAction.cxx
+++ b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/PhysicsValidationUserAction.cxx
@@ -53,13 +53,24 @@ iGeant4::PhysicsValidationUserAction::PhysicsValidationUserAction(const std::str
     m_thistSvc("THistSvc",name),
     //m_validationStream("ISFMaterial"),
     m_validationStream("ISFG4SimKernel"),
+    // branches
+    m_wzOaTr(0), m_thIn(0), m_phIn(0), m_dIn(0),
+    m_thEnd(0), m_phEnd(0), m_dEnd(0),
+    m_X0(0), m_L0(0), m_wZ(0), m_dt(0),
+    // more branches
+    m_interactions(nullptr),
+    m_process(0), m_pdg_mother(0), m_gen_mother(0), m_nChild(0),
+    m_vtx_dist(0), m_vtx_theta(0), m_vtx_phi(0), m_vtx_e_diff(0),
+    m_vtx_p_diff(0), m_vtx_plong_diff(0), m_vtx_pperp_diff(0),
+    m_p_mother(0), m_radLength(0),
     //Values taken from G4DetectorEnvelopes/EnvelopeGeometryManager.h
     m_idR(1150.-1.e-5), m_idZ(3490.),
     m_caloRmean(0.5*(40.+4250.)),  m_caloZmean(0.5*(3490.+6740.)),
     m_muonRmean(0.5*(60.+30000.)), m_muonZmean(0.5*(6740.+30000.)),
     m_cavernRmean(300000.0),  m_cavernZmean(300000.0),
     m_volumeOffset(1),
-    m_minHistoryDepth(0)
+    m_minHistoryDepth(0),
+    m_currentTrack(0)
 {
 
   ATH_MSG_DEBUG("create PhysicsValidationUserAction name: "<<name);
diff --git a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.cxx b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.cxx
index 10783e6514adc53f7dad9b5879a768aa24b8e3d0..8b35a622847e52c30933a6a6a2ee0132e963273c 100644
--- a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.cxx
+++ b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.cxx
@@ -47,6 +47,7 @@ iGeant4::G4TransportTool::G4TransportTool(const std::string& t,
                                           const IInterface*  p )
   : AthAlgTool(t,n,p),
     m_useMT(false),
+    m_pRunMgr(nullptr),
     m_UASvc("",n),
     m_userActionSvc("",n),
     m_rndmGenSvc("AtDSFMTGenSvc",n),
@@ -56,7 +57,7 @@ iGeant4::G4TransportTool::G4TransportTool(const std::string& t,
     m_physListTool("PhysicsListToolBase"),
     m_mcEventCollectionName("TruthEvent"),
     m_quasiStableParticlesIncluded(false),
-    m_worldSolid(0)
+    m_worldSolid(nullptr)
 {
 
   declareInterface<ITransportTool>(this);
@@ -86,6 +87,17 @@ iGeant4::G4TransportTool::G4TransportTool(const std::string& t,
   // Multi-threading specific settings
   declareProperty("MultiThreading", m_useMT=false);
 
+}
+
+//________________________________________________________________________
+iGeant4::G4TransportTool::~G4TransportTool()
+{}
+
+//________________________________________________________________________
+StatusCode iGeant4::G4TransportTool::initialize()
+{
+  ATH_MSG_VERBOSE("initialize");
+
   // get G4AtlasRunManager
   ATH_MSG_DEBUG("initialize G4AtlasRunManager");
 
@@ -95,24 +107,14 @@ iGeant4::G4TransportTool::G4TransportTool(const std::string& t,
     ATH_MSG_FATAL("Could not get "<<m_g4RunManagerHelper);
   }
 
-  //p_runMgr = G4AtlasRunManager::GetG4AtlasRunManager();    // clashes with use of G4HadIntProcessor
-  p_runMgr = m_g4RunManagerHelper ? m_g4RunManagerHelper->g4RunManager() : 0;
+  //m_pRunMgr = G4AtlasRunManager::GetG4AtlasRunManager();    // clashes with use of G4HadIntProcessor
+  m_pRunMgr = m_g4RunManagerHelper ? m_g4RunManagerHelper->g4RunManager() : 0;
 
   if(m_physListTool.retrieve().isFailure())
     {
       ATH_MSG_FATAL("Could not get PhysicsListToolBase");
     }
   m_physListTool->SetPhysicsList();
-}
-
-//________________________________________________________________________
-iGeant4::G4TransportTool::~G4TransportTool()
-{}
-
-//________________________________________________________________________
-StatusCode iGeant4::G4TransportTool::initialize()
-{
-  ATH_MSG_VERBOSE("initialize");
 
   // retrieve BarcodeSvc
   if ( m_barcodeSvc.retrieve().isFailure() ) {
@@ -148,7 +150,7 @@ StatusCode iGeant4::G4TransportTool::initialize()
   // V2 user action service
   if( !m_userActionSvc.name().empty() ) {
     ATH_CHECK( m_userActionSvc.retrieve() );
-    p_runMgr->SetUserActionSvc( m_userActionSvc.typeAndName() );
+    m_pRunMgr->SetUserActionSvc( m_userActionSvc.typeAndName() );
   }
 
   if(m_useMT) {
@@ -183,11 +185,11 @@ StatusCode iGeant4::G4TransportTool::initialize()
     ui->ApplyCommand("/MagneticField/Initialize");
   }
 
-  p_runMgr->SetReleaseGeo( m_releaseGeoModel );
-  p_runMgr->SetRecordFlux( m_recordFlux );
+  m_pRunMgr->SetReleaseGeo( m_releaseGeoModel );
+  m_pRunMgr->SetRecordFlux( m_recordFlux );
 
   // *AS* TEST:
-  // *AS* p_runMgr->Initialize();
+  // *AS* m_pRunMgr->Initialize();
   // *AS* but this is a good place
 
 
@@ -220,7 +222,7 @@ StatusCode iGeant4::G4TransportTool::initialize()
     ATH_MSG_FATAL("Could not get "<<m_particleBroker);
     return StatusCode::FAILURE;
     }
-    //p_runMgr->setParticleBroker(&m_particleBroker);
+    //m_pRunMgr->setParticleBroker(&m_particleBroker);
 
     if (m_particleHelper.retrieve().isSuccess())
     ATH_MSG_DEBUG("retrieved "<<m_particleHelper);
@@ -228,7 +230,7 @@ StatusCode iGeant4::G4TransportTool::initialize()
     ATH_MSG_FATAL("Could not get "<<m_particleHelper);
     return StatusCode::FAILURE;
     }
-    //p_runMgr->setParticleHelper(&m_particleHelper);
+    //m_pRunMgr->setParticleHelper(&m_particleHelper);
     */
   /*
     if (m_configTool.retrieve().isSuccess())
@@ -248,7 +250,7 @@ StatusCode iGeant4::G4TransportTool::finalize()
 
   ATH_MSG_DEBUG("\t terminating the current G4 run");
 
-  p_runMgr->RunTermination();
+  m_pRunMgr->RunTermination();
 
   return StatusCode::SUCCESS;
 }
@@ -263,7 +265,7 @@ StatusCode iGeant4::G4TransportTool::process(const ISF::ISFParticle& isp)
   G4Event* inputEvent=ISF_to_G4Event(isp);
   if (inputEvent) {
 
-    bool abort = p_runMgr->ProcessEvent(inputEvent);
+    bool abort = m_pRunMgr->ProcessEvent(inputEvent);
 
     if (abort) {
       ATH_MSG_WARNING("Event was aborted !! ");
@@ -301,7 +303,7 @@ StatusCode iGeant4::G4TransportTool::processVector(const ISF::ConstISFParticleVe
 
   G4Event* inputEvent = ISF_to_G4Event(ispVector);
   if (inputEvent) {
-    bool abort = p_runMgr->ProcessEvent(inputEvent);
+    bool abort = m_pRunMgr->ProcessEvent(inputEvent);
 
     if (abort) {
       ATH_MSG_WARNING("Event was aborted !! ");
diff --git a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.h b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.h
index 022de76a19e6ec1411cf4d271989e43b7f260cd0..3cfdb95d1136ea1d077a444cc2ac5973acf48d43 100644
--- a/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.h
+++ b/Simulation/ISF/ISF_Geant4/ISF_Geant4Tools/src/TransportTool.h
@@ -94,7 +94,7 @@ namespace iGeant4
 
     HepMC::GenEvent* genEvent() const;
 
-    G4AtlasRunManager    * p_runMgr;
+    G4AtlasRunManager    * m_pRunMgr;
 
     /// Activate multi-threading configuration
     bool m_useMT;