diff --git a/SimG4Core/Application/interface/OscarMTMasterThread.h b/SimG4Core/Application/interface/OscarMTMasterThread.h
index 09cd989f21eac..bb066beab35fd 100644
--- a/SimG4Core/Application/interface/OscarMTMasterThread.h
+++ b/SimG4Core/Application/interface/OscarMTMasterThread.h
@@ -4,9 +4,13 @@
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "FWCore/Framework/interface/ESWatcher.h"
 
-#include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"
+#include "DetectorDescription/Core/interface/DDCompactView.h"
+#include "DetectorDescription/DDCMS/interface/DDCompactView.h"
 #include "Geometry/Records/interface/IdealGeometryRecord.h"
 
+#include "HepPDT/ParticleDataTable.hh"
+#include "SimGeneral/HepPDTRecord/interface/PDTRecord.h"
+
 #include <memory>
 #include <thread>
 #include <mutex>
@@ -14,7 +18,8 @@
 
 namespace edm {
   class EventSetup;
-}
+  class ConsumesCollector;
+}  // namespace edm
 
 class RunManagerMT;
 
@@ -38,12 +43,12 @@ class OscarMTMasterThread {
   void endRun() const;
   void stopThread();
 
+  void callConsumes(edm::ConsumesCollector&& iC) const;
+
   inline RunManagerMT& runManagerMaster() const { return *m_runManagerMaster; }
   inline RunManagerMT* runManagerMasterPtr() const { return m_runManagerMaster.get(); }
 
 private:
-  void readES(const edm::EventSetup& iSetup) const;
-
   enum class ThreadState { NotExist = 0, BeginRun = 1, EndRun = 2, Destruct = 3 };
 
   const bool m_pGeoFromDD4hep;
@@ -52,12 +57,14 @@ class OscarMTMasterThread {
   std::thread m_masterThread;
 
   // ES products needed for Geant4 initialization
-  mutable edm::ESWatcher<IdealGeometryRecord> idealGeomRcdWatcher_;
-  mutable edm::ESWatcher<IdealMagneticFieldRecord> idealMagRcdWatcher_;
-  mutable const DDCompactView* m_pDD;
-  mutable const cms::DDCompactView* m_pDD4hep;
-  mutable const HepPDT::ParticleDataTable* m_pTable;
-
+  mutable const DDCompactView* m_pDDD = nullptr;
+  mutable const cms::DDCompactView* m_pDD4Hep = nullptr;
+  mutable const HepPDT::ParticleDataTable* m_pTable = nullptr;
+  mutable edm::ESGetToken<DDCompactView, IdealGeometryRecord> m_DDD;
+  mutable edm::ESGetToken<cms::DDCompactView, IdealGeometryRecord> m_DD4Hep;
+  mutable edm::ESGetToken<HepPDT::ParticleDataTable, PDTRecord> m_PDT;
+
+  // status flags
   mutable std::mutex m_protectMutex;
   mutable std::mutex m_threadMutex;
   mutable std::condition_variable m_notifyMasterCv;
@@ -65,10 +72,11 @@ class OscarMTMasterThread {
 
   mutable ThreadState m_masterThreadState;
 
-  mutable bool m_masterCanProceed;
-  mutable bool m_mainCanProceed;
-  mutable bool m_firstRun;
-  mutable bool m_stopped;
+  mutable bool m_hasToken = false;
+  mutable bool m_masterCanProceed = false;
+  mutable bool m_mainCanProceed = false;
+  mutable bool m_firstRun = true;
+  mutable bool m_stopped = false;
 };
 
 #endif
diff --git a/SimG4Core/Application/interface/RunManagerMT.h b/SimG4Core/Application/interface/RunManagerMT.h
index 093f0c48911b1..a290b6c93ae49 100644
--- a/SimG4Core/Application/interface/RunManagerMT.h
+++ b/SimG4Core/Application/interface/RunManagerMT.h
@@ -2,10 +2,7 @@
 #define SimG4Core_RunManagerMT_H
 
 #include "FWCore/Framework/interface/Event.h"
-#include "DataFormats/Common/interface/Handle.h"
-#include "FWCore/Framework/interface/EventSetup.h"
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
-#include "FWCore/Utilities/interface/InputTag.h"
 
 #include "SimG4Core/Geometry/interface/SensitiveDetectorCatalog.h"
 
@@ -59,7 +56,6 @@ class RunManagerMT {
   explicit RunManagerMT(edm::ParameterSet const&);
   ~RunManagerMT();
 
-  //  void initG4(const DDCompactView*, const cms::DDCompactView*, const MagneticField*, const HepPDT::ParticleDataTable*);
   void initG4(const DDCompactView*, const cms::DDCompactView*, const HepPDT::ParticleDataTable*);
 
   void initializeUserActions();
diff --git a/SimG4Core/Application/interface/RunManagerMTWorker.h b/SimG4Core/Application/interface/RunManagerMTWorker.h
index e1c0e65586cb6..f42895f449894 100644
--- a/SimG4Core/Application/interface/RunManagerMTWorker.h
+++ b/SimG4Core/Application/interface/RunManagerMTWorker.h
@@ -7,6 +7,9 @@
 #include "SimG4Core/Generators/interface/Generator.h"
 #include "SimDataFormats/Forward/interface/LHCTransportLinkContainer.h"
 
+#include "MagneticField/Engine/interface/MagneticField.h"
+#include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"
+
 #include <memory>
 #include <tbb/concurrent_vector.h>
 #include <unordered_map>
@@ -19,6 +22,7 @@ namespace edm {
   class ConsumesCollector;
   class HepMCProduct;
 }  // namespace edm
+
 class Generator;
 class RunManagerMT;
 
@@ -43,7 +47,7 @@ class SimProducer;
 
 class RunManagerMTWorker {
 public:
-  explicit RunManagerMTWorker(const edm::ParameterSet& iConfig, edm::ConsumesCollector&& i);
+  explicit RunManagerMTWorker(const edm::ParameterSet& iConfig, edm::ConsumesCollector&& iC);
   ~RunManagerMTWorker();
 
   void beginRun(const edm::EventSetup&);
@@ -88,6 +92,8 @@ class RunManagerMTWorker {
   edm::EDGetTokenT<edm::HepMCProduct> m_InToken;
   edm::EDGetTokenT<edm::HepMCProduct> m_LHCToken;
   edm::EDGetTokenT<edm::LHCTransportLinkContainer> m_theLHCTlinkToken;
+  edm::ESGetToken<MagneticField, IdealMagneticFieldRecord> m_MagField;
+  const MagneticField* m_pMagField = nullptr;
 
   bool m_nonBeam;
   bool m_pUseMagneticField;
diff --git a/SimG4Core/Application/plugins/OscarMTProducer.cc b/SimG4Core/Application/plugins/OscarMTProducer.cc
index 8b450dcf9264a..cfce6e9fed2d6 100644
--- a/SimG4Core/Application/plugins/OscarMTProducer.cc
+++ b/SimG4Core/Application/plugins/OscarMTProducer.cc
@@ -1,33 +1,30 @@
-#include "FWCore/PluginManager/interface/PluginManager.h"
+#include "OscarMTProducer.h"
 
+#include "FWCore/PluginManager/interface/PluginManager.h"
 #include "FWCore/Framework/interface/MakerMacros.h"
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 
-#include "OscarMTProducer.h"
+#include "FWCore/MessageLogger/interface/MessageLogger.h"
+#include "FWCore/ServiceRegistry/interface/Service.h"
+#include "FWCore/Utilities/interface/RandomNumberGenerator.h"
+#include "FWCore/Utilities/interface/Exception.h"
 
+#include "SimG4Core/Notification/interface/SimG4Exception.h"
 #include "SimG4Core/Application/interface/RunManagerMT.h"
 #include "SimG4Core/Application/interface/RunManagerMTWorker.h"
 #include "SimG4Core/Notification/interface/G4SimEvent.h"
 #include "SimG4Core/SensitiveDetector/interface/SensitiveTkDetector.h"
 #include "SimG4Core/SensitiveDetector/interface/SensitiveCaloDetector.h"
+#include "SimG4Core/Watcher/interface/SimProducer.h"
 
 #include "SimDataFormats/Track/interface/SimTrackContainer.h"
 #include "SimDataFormats/Vertex/interface/SimVertexContainer.h"
 #include "SimDataFormats/TrackingHit/interface/PSimHitContainer.h"
 #include "SimDataFormats/CaloHit/interface/PCaloHitContainer.h"
 
-#include "SimG4Core/Watcher/interface/SimProducer.h"
-
-#include "FWCore/Utilities/interface/Exception.h"
-#include "SimG4Core/Notification/interface/SimG4Exception.h"
-
-#include "FWCore/ServiceRegistry/interface/Service.h"
-#include "FWCore/Utilities/interface/RandomNumberGenerator.h"
 #include "Randomize.hh"
 
-#include "FWCore/MessageLogger/interface/MessageLogger.h"
-
 #include <iostream>
 #include <memory>
 
@@ -70,7 +67,9 @@ OscarMTProducer::OscarMTProducer(edm::ParameterSet const& p, const OscarMTMaster
 
   m_runManagerWorker = std::make_unique<RunManagerMTWorker>(p, consumesCollector());
   m_masterThread = ms;
+  m_masterThread->callConsumes(consumesCollector());
 
+  // List of produced containers
   produces<edm::SimTrackContainer>().setBranchAlias("SimTracks");
   produces<edm::SimVertexContainer>().setBranchAlias("SimVertices");
   produces<edm::PSimHitContainer>("TrackerHitsPixelBarrelLowTof");
@@ -128,9 +127,8 @@ OscarMTProducer::OscarMTProducer(edm::ParameterSet const& p, const OscarMTMaster
 
   //register any products
   auto& producers = m_runManagerWorker->producers();
-
-  for (Producers::iterator itProd = producers.begin(); itProd != producers.end(); ++itProd) {
-    (*itProd)->registerProducts(producesCollector());
+  for (auto& ptr : producers) {
+    ptr->registerProducts(producesCollector());
   }
   edm::LogVerbatim("SimG4CoreApplication") << "OscarMTProducer is constructed";
 }
@@ -145,19 +143,18 @@ std::unique_ptr<OscarMTMasterThread> OscarMTProducer::initializeGlobalCache(cons
   return std::make_unique<OscarMTMasterThread>(iConfig);
 }
 
-std::shared_ptr<int> OscarMTProducer::globalBeginRun(const edm::Run& iRun,
+std::shared_ptr<int> OscarMTProducer::globalBeginRun(const edm::Run&,
                                                      const edm::EventSetup& iSetup,
                                                      const OscarMTMasterThread* masterThread) {
   // Random number generation not allowed here
   StaticRandomEngineSetUnset random(nullptr);
-
   edm::LogVerbatim("SimG4CoreApplication") << "OscarMTProducer::globalBeginRun";
   masterThread->beginRun(iSetup);
   edm::LogVerbatim("SimG4CoreApplication") << "OscarMTProducer::globalBeginRun done";
   return std::shared_ptr<int>();
 }
 
-void OscarMTProducer::globalEndRun(const edm::Run& iRun, const edm::EventSetup& iSetup, const RunContext* iContext) {
+void OscarMTProducer::globalEndRun(const edm::Run&, const edm::EventSetup&, const RunContext* iContext) {
   edm::LogVerbatim("SimG4CoreApplication") << "OscarMTProducer::globalEndRun";
   iContext->global()->endRun();
 }
@@ -185,7 +182,7 @@ void OscarMTProducer::endRun(const edm::Run&, const edm::EventSetup&) {
 void OscarMTProducer::produce(edm::Event& e, const edm::EventSetup& es) {
   StaticRandomEngineSetUnset random(e.streamID());
   edm::LogVerbatim("SimG4CoreApplication") << "Produce event " << e.id() << " stream " << e.streamID();
-  LogDebug("SimG4CoreApplication") << "Before event rand= " << G4UniformRand();
+  //edm::LogVerbatim("SimG4CoreApplication") << " rand= " << G4UniformRand();
 
   auto& sTk = m_runManagerWorker->sensTkDetectors();
   auto& sCalo = m_runManagerWorker->sensCaloDetectors();
@@ -215,7 +212,7 @@ void OscarMTProducer::produce(edm::Event& e, const edm::EventSetup& es) {
       std::unique_ptr<edm::PSimHitContainer> product(new edm::PSimHitContainer);
       tracker->fillHits(*product, name);
       if (product != nullptr && !product->empty())
-        edm::LogVerbatim("SimG4CoreApplication") << "Produced " << product->size() << " traker hits <" << name << ">";
+        edm::LogVerbatim("SimG4CoreApplication") << "Produced " << product->size() << " tracker hits <" << name << ">";
       e.put(std::move(product), name);
     }
   }
@@ -236,7 +233,7 @@ void OscarMTProducer::produce(edm::Event& e, const edm::EventSetup& es) {
     prod.get()->produce(e, es);
   }
   edm::LogVerbatim("SimG4CoreApplication") << "Event is produced " << e.id() << " stream " << e.streamID();
-  LogDebug("SimG4CoreApplication") << "End of event rand= " << G4UniformRand();
+  //edm::LogVerbatim("SimG4CoreApplication") << " rand= " << G4UniformRand();
 }
 
 StaticRandomEngineSetUnset::StaticRandomEngineSetUnset(edm::StreamID const& streamID) {
diff --git a/SimG4Core/Application/plugins/OscarMTProducer.h b/SimG4Core/Application/plugins/OscarMTProducer.h
index bd6765444310b..5d9bc43ce25d7 100644
--- a/SimG4Core/Application/plugins/OscarMTProducer.h
+++ b/SimG4Core/Application/plugins/OscarMTProducer.h
@@ -3,7 +3,6 @@
 
 #include "FWCore/Framework/interface/stream/EDProducer.h"
 #include "FWCore/Framework/interface/Event.h"
-#include "DataFormats/Common/interface/Handle.h"
 #include "FWCore/Framework/interface/MakerMacros.h"
 #include "FWCore/Framework/interface/EventSetup.h"
 #include "FWCore/Framework/interface/Run.h"
diff --git a/SimG4Core/Application/src/OscarMTMasterThread.cc b/SimG4Core/Application/src/OscarMTMasterThread.cc
index 575665607901d..468e2196c0810 100644
--- a/SimG4Core/Application/src/OscarMTMasterThread.cc
+++ b/SimG4Core/Application/src/OscarMTMasterThread.cc
@@ -1,40 +1,24 @@
 #include <memory>
 
 #include "SimG4Core/Application/interface/OscarMTMasterThread.h"
+#include "FWCore/Utilities/interface/EDMException.h"
+#include "FWCore/Framework/interface/ConsumesCollector.h"
 
 #include "SimG4Core/Application/interface/RunManagerMT.h"
 #include "SimG4Core/Geometry/interface/CustomUIsession.h"
 
-#include "FWCore/Framework/interface/EventSetup.h"
-#include "FWCore/Framework/interface/ESHandle.h"
-#include "FWCore/Framework/interface/ESTransientHandle.h"
-#include "FWCore/Utilities/interface/EDMException.h"
-
-#include "Geometry/Records/interface/IdealGeometryRecord.h"
-#include "DetectorDescription/Core/interface/DDCompactView.h"
-#include "DetectorDescription/DDCMS/interface/DDCompactView.h"
-
-#include "HepPDT/ParticleDataTable.hh"
-#include "SimGeneral/HepPDTRecord/interface/PDTRecord.h"
-
 #include "G4PhysicalVolumeStore.hh"
 
 OscarMTMasterThread::OscarMTMasterThread(const edm::ParameterSet& iConfig)
     : m_pGeoFromDD4hep(iConfig.getParameter<bool>("g4GeometryDD4hepSource")),
-      m_pDD(nullptr),
-      m_pDD4hep(nullptr),
-      m_pTable(nullptr),
-      m_masterThreadState(ThreadState::NotExist),
-      m_masterCanProceed(false),
-      m_mainCanProceed(false),
-      m_firstRun(true),
-      m_stopped(false) {
+      m_masterThreadState(ThreadState::NotExist) {
   // Lock the mutex
   std::unique_lock<std::mutex> lk(m_threadMutex);
 
-  edm::LogVerbatim("SimG4CoreApplication") << "OscarMTMasterThread: creating master thread";
+  edm::LogVerbatim("SimG4CoreApplication")
+      << "OscarMTMasterThread: creating master thread DD4Hep: " << m_pGeoFromDD4hep;
 
-  // Create Genat4 master thread
+  // Create Geant4 master thread
   m_masterThread = std::thread([&]() {
     /////////////////
     // Initialization
@@ -64,6 +48,7 @@ OscarMTMasterThread::OscarMTMasterThread(const edm::ParameterSet& iConfig)
       m_masterCanProceed = false;
       edm::LogVerbatim("OscarMTMasterThread") << "Master thread: State loop, starting wait";
       m_notifyMasterCv.wait(lk2, [&] { return m_masterCanProceed; });
+      //m_notifyMasterCv.wait(lk2, [&] { return false; });
 
       // Act according to the state
       edm::LogVerbatim("OscarMTMasterThread")
@@ -71,7 +56,7 @@ OscarMTMasterThread::OscarMTMasterThread(const edm::ParameterSet& iConfig)
       if (m_masterThreadState == ThreadState::BeginRun) {
         // Initialize Geant4
         edm::LogVerbatim("OscarMTMasterThread") << "Master thread: Initializing Geant4";
-        m_runManagerMaster->initG4(m_pDD, m_pDD4hep, m_pTable);
+        m_runManagerMaster->initG4(m_pDDD, m_pDD4Hep, m_pTable);
         isG4Alive = true;
       } else if (m_masterThreadState == ThreadState::EndRun) {
         // Stop Geant4
@@ -119,14 +104,33 @@ OscarMTMasterThread::~OscarMTMasterThread() {
   }
 }
 
+void OscarMTMasterThread::callConsumes(edm::ConsumesCollector&& iC) const {
+  if (m_hasToken) {
+    return;
+  }
+  if (m_pGeoFromDD4hep) {
+    m_DD4Hep = iC.esConsumes<cms::DDCompactView, IdealGeometryRecord, edm::Transition::BeginRun>();
+  } else {
+    m_DDD = iC.esConsumes<DDCompactView, IdealGeometryRecord, edm::Transition::BeginRun>();
+  }
+  m_PDT = iC.esConsumes<HepPDT::ParticleDataTable, PDTRecord, edm::Transition::BeginRun>();
+  m_hasToken = true;
+}
+
 void OscarMTMasterThread::beginRun(const edm::EventSetup& iSetup) const {
   std::lock_guard<std::mutex> lk(m_protectMutex);
-
   std::unique_lock<std::mutex> lk2(m_threadMutex);
+  edm::LogVerbatim("SimG4CoreApplication") << "OscarMTMasterThread::beginRun";
 
-  // Reading from ES must be done in the main (CMSSW) thread
-  readES(iSetup);
-
+  if (m_firstRun) {
+    if (m_pGeoFromDD4hep) {
+      m_pDD4Hep = &(*iSetup.getTransientHandle(m_DD4Hep));
+    } else {
+      m_pDDD = &(*iSetup.getTransientHandle(m_DDD));
+    }
+    m_pTable = &iSetup.getData(m_PDT);
+    m_firstRun = false;
+  }
   m_masterThreadState = ThreadState::BeginRun;
   m_masterCanProceed = true;
   m_mainCanProceed = false;
@@ -140,8 +144,8 @@ void OscarMTMasterThread::beginRun(const edm::EventSetup& iSetup) const {
 
 void OscarMTMasterThread::endRun() const {
   std::lock_guard<std::mutex> lk(m_protectMutex);
-
   std::unique_lock<std::mutex> lk2(m_threadMutex);
+
   m_masterThreadState = ThreadState::EndRun;
   m_mainCanProceed = false;
   m_masterCanProceed = true;
@@ -176,33 +180,3 @@ void OscarMTMasterThread::stopThread() {
   edm::LogVerbatim("SimG4CoreApplication") << "OscarMTMasterThread::stopTread: main thread finished";
   m_stopped = true;
 }
-
-void OscarMTMasterThread::readES(const edm::EventSetup& iSetup) const {
-  bool geomChanged = idealGeomRcdWatcher_.check(iSetup);
-  if (geomChanged && (!m_firstRun)) {
-    throw edm::Exception(edm::errors::Configuration)
-        << "[SimG4Core OscarMTMasterThread]\n"
-        << "The Geometry configuration is changed during the job execution\n"
-        << "this is not allowed, the geometry must stay unchanged";
-  }
-  // Don't read from ES if not the first run, just as in
-  if (!m_firstRun)
-    return;
-
-  // DDDWorld: get the DDCV from the ES and use it to build the World
-  if (m_pGeoFromDD4hep) {
-    edm::ESTransientHandle<cms::DDCompactView> pDD;
-    iSetup.get<IdealGeometryRecord>().get(pDD);
-    m_pDD4hep = pDD.product();
-  } else {
-    edm::ESTransientHandle<DDCompactView> pDD;
-    iSetup.get<IdealGeometryRecord>().get(pDD);
-    m_pDD = pDD.product();
-  }
-
-  edm::ESHandle<HepPDT::ParticleDataTable> fTable;
-  iSetup.get<PDTRecord>().get(fTable);
-  m_pTable = fTable.product();
-
-  m_firstRun = false;
-}
diff --git a/SimG4Core/Application/src/RunManagerMT.cc b/SimG4Core/Application/src/RunManagerMT.cc
index bc79172131078..22b69f68bf938 100644
--- a/SimG4Core/Application/src/RunManagerMT.cc
+++ b/SimG4Core/Application/src/RunManagerMT.cc
@@ -203,11 +203,6 @@ void RunManagerMT::initG4(const DDCompactView* pDD,
     throw edm::Exception(edm::errors::LogicError, "G4RunManagerKernel initialization failed!");
   }
 
-  timer.Stop();
-  G4cout.precision(4);
-  G4cout << "RunManagerMT: physics is initialized: " << timer << G4endl;
-  timer.Start();
-
   if (m_StorePhysicsTables) {
     std::ostringstream dir;
     dir << m_PhysicsTablesDir << '\0';
diff --git a/SimG4Core/Application/src/RunManagerMTWorker.cc b/SimG4Core/Application/src/RunManagerMTWorker.cc
index 6d47628f2ddf7..7771f3f4a7e7e 100644
--- a/SimG4Core/Application/src/RunManagerMTWorker.cc
+++ b/SimG4Core/Application/src/RunManagerMTWorker.cc
@@ -16,7 +16,6 @@
 #include "FWCore/MessageLogger/interface/MessageLogger.h"
 #include "FWCore/Framework/interface/Event.h"
 #include "FWCore/Framework/interface/EventSetup.h"
-#include "DataFormats/Common/interface/Handle.h"
 #include "FWCore/Framework/interface/ConsumesCollector.h"
 #include "FWCore/ServiceRegistry/interface/Service.h"
 #include "FWCore/Utilities/interface/thread_safety_macros.h"
@@ -28,19 +27,12 @@
 #include "SimG4Core/Notification/interface/CMSSteppingVerbose.h"
 #include "SimG4Core/Watcher/interface/SimWatcherFactory.h"
 
-#include "FWCore/Framework/interface/EventSetup.h"
-#include "FWCore/Framework/interface/ESHandle.h"
-#include "FWCore/Framework/interface/ESTransientHandle.h"
-#include "Geometry/Records/interface/IdealGeometryRecord.h"
-
 #include "SimG4Core/Geometry/interface/DDDWorld.h"
 #include "SimG4Core/MagneticField/interface/FieldBuilder.h"
 #include "SimG4Core/MagneticField/interface/CMSFieldManager.h"
 
-#include "MagneticField/Engine/interface/MagneticField.h"
-#include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"
-
 #include "SimDataFormats/GeneratorProducts/interface/HepMCProduct.h"
+#include "DataFormats/GeometryVector/interface/GlobalPoint.h"
 
 #include "SimG4Core/Physics/interface/PhysicsList.h"
 
@@ -176,6 +168,9 @@ RunManagerMTWorker::RunManagerMTWorker(const edm::ParameterSet& iConfig, edm::Co
   if (m_LHCTransport) {
     m_LHCToken = iC.consumes<edm::HepMCProduct>(edm::InputTag("LHCTransport"));
   }
+  if (m_pUseMagneticField) {
+    m_MagField = iC.esConsumes<MagneticField, IdealMagneticFieldRecord, edm::Transition::BeginRun>();
+  }
   edm::LogVerbatim("SimG4CoreApplication") << "RunManagerMTWorker is constructed for the thread " << thisID;
   unsigned int k = 0;
   for (std::unordered_map<std::string, std::unique_ptr<SensitiveDetectorMakerBase>>::const_iterator itr =
@@ -315,12 +310,11 @@ void RunManagerMTWorker::initializeG4(RunManagerMT* runManagerMaster, const edm:
 
   // setup the magnetic field
   if (m_pUseMagneticField) {
-    const GlobalPoint g(0., 0., 0.);
+    const GlobalPoint g(0.f, 0.f, 0.f);
 
-    edm::ESHandle<MagneticField> pMF;
-    es.get<IdealMagneticFieldRecord>().get(pMF);
+    m_pMagField = &es.getData(m_MagField);
+    sim::FieldBuilder fieldBuilder(m_pMagField, m_pField);
 
-    sim::FieldBuilder fieldBuilder(pMF.product(), m_pField);
     CMSFieldManager* fieldManager = new CMSFieldManager();
     tM->SetFieldManager(fieldManager);
     fieldBuilder.build(fieldManager, tM->GetPropagatorInField());
diff --git a/SimG4Core/Watcher/interface/SimProducer.h b/SimG4Core/Watcher/interface/SimProducer.h
index 8292ecd1199e6..8e8b95ef44660 100644
--- a/SimG4Core/Watcher/interface/SimProducer.h
+++ b/SimG4Core/Watcher/interface/SimProducer.h
@@ -64,13 +64,7 @@ namespace simproducer {
 class SimProducer : public SimWatcher {
 public:
   SimProducer() {}
-  // virtual ~SimProducer();
 
-  // ---------- const member functions ---------------------
-
-  // ---------- static member functions --------------------
-
-  // ---------- member functions ---------------------------
   virtual void produce(edm::Event &, const edm::EventSetup &) = 0;
 
   void registerProducts(edm::ProducesCollector producesCollector) {
@@ -81,6 +75,9 @@ class SimProducer : public SimWatcher {
                   });
   }
 
+  SimProducer(const SimProducer &) = delete;
+  const SimProducer &operator=(const SimProducer &) = delete;
+
 protected:
   template <class T>
   void produces() {
@@ -93,11 +90,6 @@ class SimProducer : public SimWatcher {
   }
 
 private:
-  SimProducer(const SimProducer &) = delete;  // stop default
-
-  const SimProducer &operator=(const SimProducer &) = delete;  // stop default
-
-  // ---------- member data --------------------------------
   std::vector<std::shared_ptr<simproducer::ProductInfoBase>> m_info;
 };