diff --git a/include/openmc/dagmc.h b/include/openmc/dagmc.h
index adc4f47f1f..d3012e3a0a 100644
--- a/include/openmc/dagmc.h
+++ b/include/openmc/dagmc.h
@@ -14,10 +14,14 @@ extern "C" const bool dagmc_enabled;
 
 namespace openmc {
 
-extern moab::DagMC::RayHistory history;
-extern Direction last_dir;
+namespace simulation {
+
+extern moab::DagMC::RayHistory history; //!< facet history for DagMC particles
+extern Direction last_dir; //!< last direction passed to DagMC's ray_fire
 #pragma omp threadprivate(history, last_dir)
 
+}
+
 namespace model {
   extern moab::DagMC* DAG;
 }
diff --git a/src/cell.cpp b/src/cell.cpp
index 4ad114b7ed..a65d07f3c4 100644
--- a/src/cell.cpp
+++ b/src/cell.cpp
@@ -617,9 +617,9 @@ DAGCell::distance(Position r, Direction u, int32_t on_surface) const
 {
   // if we've changed direction or we're not on a surface,
   // reset the history and update last direction
-  if (u != last_dir || on_surface == 0) {
-    history.reset();
-    last_dir = u;
+  if (u != simulation::last_dir || on_surface == 0) {
+    simulation::history.reset();
+    simulation::last_dir = u;
   }
 
   moab::ErrorCode rval;
@@ -628,7 +628,7 @@ DAGCell::distance(Position r, Direction u, int32_t on_surface) const
   double dist;
   double pnt[3] = {r.x, r.y, r.z};
   double dir[3] = {u.x, u.y, u.z};
-  rval = dagmc_ptr_->ray_fire(vol, pnt, dir, hit_surf, dist, &history);
+  rval = dagmc_ptr_->ray_fire(vol, pnt, dir, hit_surf, dist, &simulation::history);
   MB_CHK_ERR_CONT(rval);
   int surf_idx;
   if (hit_surf != 0) {
diff --git a/src/dagmc.cpp b/src/dagmc.cpp
index 05e0659415..78d8bc4fb6 100644
--- a/src/dagmc.cpp
+++ b/src/dagmc.cpp
@@ -38,9 +38,15 @@ const bool dagmc_enabled = false;
 const std::string DAGMC_FILENAME = "dagmc.h5m";
 
 namespace openmc {
+
+
+namespace simulation {
+
 moab::DagMC::RayHistory history;
 Direction last_dir;
 
+}
+
 namespace model {
 
 moab::DagMC* DAG;
diff --git a/src/particle.cpp b/src/particle.cpp
index eef58a490d..afcc56317f 100644
--- a/src/particle.cpp
+++ b/src/particle.cpp
@@ -373,9 +373,7 @@ Particle::transport()
   }
 
   #ifdef DAGMC
-  if(settings::dagmc) {
-    history.reset();
-  }
+  if (settings::dagmc) simulation::history.reset();
   #endif
 
   // Finish particle track output.
diff --git a/src/surface.cpp b/src/surface.cpp
index a643d52730..a33607b775 100644
--- a/src/surface.cpp
+++ b/src/surface.cpp
@@ -266,9 +266,9 @@ Direction DAGSurface::normal(Position r) const
 
 Direction DAGSurface::reflect(Position r, Direction u) const
 {
-  history.reset_to_last_intersection();
-  last_dir = Surface::reflect(r, u);
-  return last_dir;
+  simulation::history.reset_to_last_intersection();
+  simulation::last_dir = Surface::reflect(r, u);
+  return simulation::last_dir;
 }
 
 BoundingBox DAGSurface::bounding_box() const