diff --git a/Simulation/ISF/ISF_HepMC/ISF_HepMC_Tools/python/ISF_HepMC_ToolsConfig.py b/Simulation/ISF/ISF_HepMC/ISF_HepMC_Tools/python/ISF_HepMC_ToolsConfig.py
index e504bdbc6de0746ddb2302c2c8fe1b84661dfdf3..0fcf1910cc877ec6b8d495f70358f2d7b15a1d0a 100644
--- a/Simulation/ISF/ISF_HepMC/ISF_HepMC_Tools/python/ISF_HepMC_ToolsConfig.py
+++ b/Simulation/ISF/ISF_HepMC/ISF_HepMC_Tools/python/ISF_HepMC_ToolsConfig.py
@@ -86,7 +86,7 @@ def getParticlePositionFilterDynamic(name="ISF_ParticlePositionFilterDynamic", *
 def getGenParticleInteractingFilter(name="ISF_GenParticleInteractingFilter", **kwargs):
     from G4AtlasApps.SimFlags import simFlags
     simdict = simFlags.specialConfiguration.get_Value()
-    if "InteractingPDGCodes" in simdict:
+    if simdict is not None and "InteractingPDGCodes" in simdict:
         kwargs.setdefault('AdditionalInteractingParticleTypes', simdict["InteractingPDGCodes"])
     return CfgMgr.ISF__GenParticleInteractingFilter(name, **kwargs)