diff --git a/Simulation/G4Utilities/Geo2G4/src/Geo2G4OpticalSurfaceFactory.cxx b/Simulation/G4Utilities/Geo2G4/src/Geo2G4OpticalSurfaceFactory.cxx
index 3af74f855bbd89eeaabbb4cc48dad4e3e14d285d..eac93dbfc87d7c185c72bfa7c209533ea3acefca 100644
--- a/Simulation/G4Utilities/Geo2G4/src/Geo2G4OpticalSurfaceFactory.cxx
+++ b/Simulation/G4Utilities/Geo2G4/src/Geo2G4OpticalSurfaceFactory.cxx
@@ -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
 */
 
 #include "Geo2G4OpticalSurfaceFactory.h"
@@ -115,7 +115,7 @@ G4OpticalSurface* Geo2G4OpticalSurfaceFactory::Build(const GeoOpticalSurface* ge
 
   // Create material properties table
   Geo2G4MatPropTableFactory* tFactory = Geo2G4MatPropTableFactory::instance();
-  GeoMaterialPropertiesTable* geoPropTable = geoOpticalSurface->GetMaterialPropertiesTable();
+  const GeoMaterialPropertiesTable* geoPropTable = geoOpticalSurface->GetMaterialPropertiesTable();
 
   if(geoPropTable){
     G4MaterialPropertiesTable* g4PropTable = tFactory->Build(geoPropTable);
diff --git a/Simulation/G4Utilities/GeoMaterial2G4/src/Geo2G4MaterialFactory.cxx b/Simulation/G4Utilities/GeoMaterial2G4/src/Geo2G4MaterialFactory.cxx
index 1857d60c60e39a32ae2c39c532a20305ef59683d..24ae3b3d4a4e32b890dbb7aa9b4be26b4964cfe9 100644
--- a/Simulation/G4Utilities/GeoMaterial2G4/src/Geo2G4MaterialFactory.cxx
+++ b/Simulation/G4Utilities/GeoMaterial2G4/src/Geo2G4MaterialFactory.cxx
@@ -75,7 +75,7 @@ G4Material* Geo2G4MaterialFactory::Build(const GeoMaterial* geoMaterial)
                                pressure);
 
     // Build G4MaterialPropertiesTable if needed
-    GeoMaterialPropertiesTable* geoPropTable = extMat->GetMaterialPropertiesTable();
+    const GeoMaterialPropertiesTable* geoPropTable = extMat->GetMaterialPropertiesTable();
 
     if(geoPropTable) {
       G4MaterialPropertiesTable* g4PropTable = tFactory->Build(geoPropTable);