diff --git a/include/openmc/geometry.h b/include/openmc/geometry.h
index a7ac53ea3..6947201a2 100644
--- a/include/openmc/geometry.h
+++ b/include/openmc/geometry.h
@@ -7,7 +7,7 @@
 #include <vector>
 
 #include "openmc/particle.h"
-#include "openmc/tallies/filter.h"
+//#include "openmc/tallies/filter.h"
 
 
 namespace openmc {
diff --git a/include/openmc/particle.h b/include/openmc/particle.h
index 62d80ca1e..5d87f7b15 100644
--- a/include/openmc/particle.h
+++ b/include/openmc/particle.h
@@ -226,8 +226,7 @@ public:
   //! \param src Source site data
   void from_source(const Bank* src);
 
-  void event_calculate_xs_I();
-  void event_calculate_xs_II();
+  void event_calculate_xs();
   void event_advance();
   void event_cross_surface();
   void event_collide();
diff --git a/src/particle.cpp b/src/particle.cpp
index 8417a9184..29ab456a7 100644
--- a/src/particle.cpp
+++ b/src/particle.cpp
@@ -130,7 +130,7 @@ Particle::from_source(const Bank* src)
 }
 
 void
-Particle::event_calculate_xs_I()
+Particle::event_calculate_xs()
 {
     // Set the random number stream
     if (type_ == Particle::Type::neutron) {
@@ -168,11 +168,7 @@ Particle::event_calculate_xs_I()
     if (write_track_) write_particle_track(*this);
 
     if (settings::check_overlaps) check_cell_overlap(this);
-}
-
-void
-Particle::event_calculate_xs_II()
-{
+    
     // Calculate microscopic and macroscopic cross sections
     if (material_ != MATERIAL_VOID) {
       if (settings::run_CE) {
diff --git a/src/simulation.cpp b/src/simulation.cpp
index 85b2bf6be..cb603c403 100644
--- a/src/simulation.cpp
+++ b/src/simulation.cpp
@@ -2,30 +2,23 @@
 
 #include "openmc/bank.h"
 #include "openmc/capi.h"
-//#include "openmc/cell.h"
 #include "openmc/container_util.h"
 #include "openmc/eigenvalue.h"
 #include "openmc/error.h"
-//#include "openmc/geometry.h"
 #include "openmc/material.h"
 #include "openmc/message_passing.h"
-//#include "openmc/mgxs_interface.h"
 #include "openmc/nuclide.h"
 #include "openmc/output.h"
 #include "openmc/particle.h"
 #include "openmc/photon.h"
-//#include "openmc/physics.h"
-//#include "openmc/physics_mg.h"
 #include "openmc/random_lcg.h"
 #include "openmc/settings.h"
 #include "openmc/source.h"
 #include "openmc/state_point.h"
-//#include "openmc/thermal.h"
 #include "openmc/timer.h"
 #include "openmc/tallies/derivative.h"
 #include "openmc/tallies/filter.h"
 #include "openmc/tallies/tally.h"
-//#include "openmc/tallies/tally_scoring.h"
 #include "openmc/tallies/trigger.h"
 #include "openmc/track_output.h"
 
@@ -47,8 +40,7 @@ namespace openmc {
 void transport_history_based_single_particle(Particle& p)
 {
   while(true) {
-    p.event_calculate_xs_I();
-    p.event_calculate_xs_II();
+    p.event_calculate_xs();
     p.event_advance();
     if( p.collision_distance_ > p.boundary_.distance ) 
       p.event_cross_surface();