diff --git a/CepGen/IO/HepMCHandler.cpp b/CepGen/IO/HepMCHandler.cpp
index a88cfe4..1be1592 100644
--- a/CepGen/IO/HepMCHandler.cpp
+++ b/CepGen/IO/HepMCHandler.cpp
@@ -1,129 +1,137 @@
 #include "CepGen/IO/ExportHandler.h"
 #include "CepGen/IO/HepMCEventInterface.h"
 
 #include "CepGen/Parameters.h"
 #include "CepGen/Core/Exception.h"
 #include "CepGen/Core/ParametersList.h"
 
 #include "CepGen/Event/Event.h"
 #include "CepGen/Physics/Constants.h"
 
 #ifdef HEPMC3
 #  include "HepMC3/Version.h"
 #  define HEPMC_VERSION HEPMC3_VERSION
 #  define HEPMC_VERSION_CODE HEPMC3_VERSION_CODE
 #  include "HepMC3/WriterAscii.h"
 #  include "HepMC3/WriterAsciiHepMC2.h"
 #  include "HepMC3/WriterHEPEVT.h"
 #  ifdef HEPMC3_ROOTIO
 #    include "HepMC3/WriterRoot.h"
 #    include "HepMC3/WriterRootTree.h"
 #  endif
 #else
 #  include "HepMC/Version.h"
 #  if !defined( HEPMC_VERSION_CODE ) // HepMC v2
 #    include "HepMC/IO_GenEvent.h"
 #  else
 #    include "HepMC/WriterAscii.h"
 #    include "HepMC/WriterHEPEVT.h"
 #    define HEPMC3
 #  endif
 #endif
 
 #include <memory>
 
 using namespace HepMC;
 
 namespace cepgen
 {
   namespace io
   {
     /// Handler for the HepMC file output
     /// \tparam T HepMC writer handler (format-dependent)
     /// \author Laurent Forthomme <laurent.forthomme@cern.ch>
     /// \date Sep 2016
     template<typename T>
     class HepMCHandler : public GenericExportHandler
     {
       public:
         /// Class constructor
         explicit HepMCHandler( const ParametersList& );
+        ~HepMCHandler();
+
         void initialise( const Parameters& /*params*/ ) override {}
         /// Writer operator
         void operator<<( const Event& ) override;
         void setCrossSection( double, double ) override;
 
       private:
         /// Writer object
         std::unique_ptr<T> output_;
         /// Generator cross section and error
         std::shared_ptr<GenCrossSection> xs_;
 #ifdef HEPMC3
         /// Auxiliary information on run
         std::shared_ptr<GenRunInfo> runinfo_;
 #endif
         /// Associated HepMC event
         std::shared_ptr<CepGenEvent> event_;
     };
 
     template<typename T>
     HepMCHandler<T>::HepMCHandler( const ParametersList& params ) :
       GenericExportHandler( "hepmc" ),
       output_( new T( params.get<std::string>( "filename", "output.hepmc" ) ) ),
       xs_( new GenCrossSection ),
 #ifdef HEPMC3
       runinfo_( new GenRunInfo ),
 #endif
       event_( new CepGenEvent )
     {
 #ifdef HEPMC3
       output_->set_run_info( runinfo_ );
       runinfo_->set_weight_names( { "Default" } );
 #endif
       CG_INFO( "HepMC" )
         << "Interfacing module initialised "
         << "for HepMC version " << HEPMC_VERSION << ".";
     }
 
+    template<typename T>
+    HepMCHandler<T>::~HepMCHandler()
+    {
+      output_->close();
+    }
+
     template<typename T> void
     HepMCHandler<T>::operator<<( const Event& evt )
     {
       event_->feedEvent( evt );
       // general information
 #ifdef HEPMC3
       event_->set_cross_section( xs_ );
       event_->set_run_info( runinfo_ );
 #else
       event_->set_cross_section( *xs_ );
 #endif
       event_->set_event_number( event_num_++ );
 #ifdef HEPMC3
       output_->write_event( *event_ );
 #else
       output_->write_event( event_.get() );
 #endif
     }
 
     template<typename T> void
     HepMCHandler<T>::setCrossSection( double xsect, double xsect_err )
     {
       xs_->set_cross_section( xsect, xsect_err );
     }
   }
 }
 
 #ifdef HEPMC3
 REGISTER_IO_MODULE( hepmc, HepMCHandler<WriterAscii> )
 REGISTER_IO_MODULE( hepmc3, HepMCHandler<WriterAscii> )
 REGISTER_IO_MODULE( hepevt, HepMCHandler<WriterHEPEVT> )
 #  if HEPMC_VERSION_CODE >= 3001000
 REGISTER_IO_MODULE( hepmc2, HepMCHandler<WriterAsciiHepMC2> )
 #  endif
 #  ifdef HEPMC3_ROOTIO
 REGISTER_IO_MODULE( hepmc_root, HepMCHandler<WriterRoot> )
 REGISTER_IO_MODULE( hepmc_root_tree, HepMCHandler<WriterRootTree> )
 #  endif
 #else
 REGISTER_IO_MODULE( hepmc, HepMCHandler<IO_GenEvent> )
 #endif