diff --git a/pytential/qbx/refinement.py b/pytential/qbx/refinement.py
index 829e706c481227bbc49b3e524094555cb1f541b8..5e1afca22e24766ec76510e78072f30b09d9f70f 100644
--- a/pytential/qbx/refinement.py
+++ b/pytential/qbx/refinement.py
@@ -144,8 +144,8 @@ EXPANSION_DISK_UNDISTURBED_BY_SOURCES_CHECKER = AreaQueryElementwiseTemplate(
 
             if (is_close)
             {
-                panel_refine_flags[center_panel] = 1;
-                *found_panel_to_refine = 1;
+                atomic_or(&panel_refine_flags[center_panel], 1);
+                atomic_or(found_panel_to_refine, 1);
                 break;
             }
         }
@@ -203,8 +203,8 @@ SUFFICIENT_SOURCE_QUADRATURE_RESOLUTION_CHECKER = AreaQueryElementwiseTemplate(
 
             if (is_close)
             {
-                panel_refine_flags[my_panel] = 1;
-                *found_panel_to_refine = 1;
+                atomic_or(&panel_refine_flags[my_panel], 1);
+                atomic_or(found_panel_to_refine, 1);
                 break;
             }
         }
@@ -252,10 +252,14 @@ class RefinerCodeContainer(TreeCodeContainerMixin):
                 <> over_threshold = element_property[ielement] > threshold
                 if over_threshold
                     refine_flags[ielement] = 1
-                    refine_flags_updated = 1 {id=write_refine_flags_updated}
+                    refine_flags_updated = 1 {id=write_refine_flags_updated, atomic}
                 end
             end
             """,
+            [
+                lp.GlobalArg("refine_flags_updated", shape=(), for_atomic=True),
+                "..."
+                ],
             options="return_dict",
             silenced_warnings="write_race(write_refine_flags_updated)",
             name="refine_kernel_length_scale_to_quad_resolution_ratio",
diff --git a/pytential/qbx/target_assoc.py b/pytential/qbx/target_assoc.py
index d8f32f54fd9e72e8d3fdadd6612a2087ef839ecf..27658c8a7043d27e2a9f520da9ca1cec4c2214fe 100644
--- a/pytential/qbx/target_assoc.py
+++ b/pytential/qbx/target_assoc.py
@@ -208,7 +208,7 @@ QBX_TARGET_MARKER = AreaQueryElementwiseTemplate(
                     <= tunnel_radius_by_source[source])
             {
                 target_status[i] = MARKED_QBX_CENTER_PENDING;
-                *found_target_close_to_panel = 1;
+                atomic_or(found_target_close_to_panel, 1);
             }
         }
     """,
@@ -401,8 +401,8 @@ QBX_FAILED_TARGET_ASSOCIATION_REFINER = AreaQueryElementwiseTemplate(
             {
                 particle_id_t panel = bsearch(
                     panel_to_source_starts, npanels + 1, source);
-                refine_flags[panel] = 1;
-                *found_panel_to_refine = 1;
+                atomic_or(&refine_flags[panel], 1);
+                atomic_or(found_panel_to_refine, 1);
             }
         }
     """,