diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3cfea2227f..7ecd6e3211 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -433,6 +433,7 @@ set(LIBOPENMC_FORTRAN_SRC
 )
 set(LIBOPENMC_CXX_SRC
   src/initialize.cpp
+  src/finalize.cpp
   src/hdf5_interface.cpp
   src/message_passing.cpp
   src/plot.cpp
diff --git a/src/api.F90 b/src/api.F90
index 49d86edb67..bc0757be57 100644
--- a/src/api.F90
+++ b/src/api.F90
@@ -105,6 +105,11 @@ contains
   function openmc_finalize() result(err) bind(C)
     integer(C_INT) :: err
 
+    interface
+      subroutine openmc_free_bank() bind(C)
+      end subroutine openmc_free_bank
+    end interface
+
     ! Clear results
     err = openmc_reset()
 
@@ -170,6 +175,7 @@ contains
 #ifdef OPENMC_MPI
     ! Free all MPI types
     call MPI_TYPE_FREE(MPI_BANK, err)
+    call openmc_free_bank()
 #endif
 
   end function openmc_finalize
diff --git a/src/finalize.cpp b/src/finalize.cpp
new file mode 100644
index 0000000000..696a1e80e5
--- /dev/null
+++ b/src/finalize.cpp
@@ -0,0 +1,10 @@
+#include "finalize.h"
+
+#include "message_passing.h"
+
+void openmc_free_bank()
+{
+#ifdef OPENMC_MPI
+  MPI_Type_free(&openmc::mpi::bank);
+#endif
+}
diff --git a/src/finalize.h b/src/finalize.h
new file mode 100644
index 0000000000..e606493ca1
--- /dev/null
+++ b/src/finalize.h
@@ -0,0 +1,6 @@
+#ifndef FINALIZE_H
+#define FINALIZE_H
+
+extern "C" void openmc_free_bank();
+
+#endif // FINALIZE_H
diff --git a/src/hdf5_interface.F90 b/src/hdf5_interface.F90
index 3fd5e860fd..40f56d88ef 100644
--- a/src/hdf5_interface.F90
+++ b/src/hdf5_interface.F90
@@ -1103,7 +1103,7 @@ contains
     character(*), intent(in), target   :: buffer(:)  ! read data to here
     logical,      intent(in), optional :: indep ! independent I/O
 
-    integer :: i
+    integer(HSIZE_T) :: i
     integer(HSIZE_T) :: dims(1)
     integer(C_SIZE_T) :: m, n
     logical(C_BOOL) :: indep_
diff --git a/src/initialize.cpp b/src/initialize.cpp
index d8045e4337..c7c37e31db 100644
--- a/src/initialize.cpp
+++ b/src/initialize.cpp
@@ -71,7 +71,8 @@ void initialize_mpi(MPI_Comm intracomm)
 
   // Initialize MPI
   int flag;
-  if (!MPI_Initialized(&flag)) MPI_Init(nullptr, nullptr);
+  MPI_Initialized(&flag);
+  if (!flag) MPI_Init(nullptr, nullptr);
 
   // Determine number of processes and rank for each
   MPI_Comm_size(intracomm, &openmc::mpi::n_procs);
diff --git a/src/main.cpp b/src/main.cpp
index 42593dc658..6d0cf1f268 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -38,12 +38,14 @@ int main(int argc, char* argv[]) {
     err = openmc_calculate_volumes();
     break;
   }
+  if (err) openmc::fatal_error(openmc_err_msg);
 
   // Finalize and free up memory
-  openmc_finalize();
+  err = openmc_finalize();
+  if (err) openmc::fatal_error(openmc_err_msg);
 
   // If MPI is in use and enabled, terminate it
-#ifdef MPI
+#ifdef OPENMC_MPI
   MPI_Finalize();
 #endif
 }