diff --git a/CIME/XML/env_mach_pes.py b/CIME/XML/env_mach_pes.py
index 1da8fff6f0c..76c6588901b 100644
--- a/CIME/XML/env_mach_pes.py
+++ b/CIME/XML/env_mach_pes.py
@@ -181,7 +181,8 @@ def get_tasks_per_node(self, total_tasks, max_thread_count):
             else:
                 tasks_per_node = self.get_value("MAX_MPITASKS_PER_NODE")
         else:
-            if self.get_value("NGPUS_PER_NODE") > 0:
+            ngpus_per_node = self.get_value("NGPUS_PER_NODE")
+            if ngpus_per_node and ngpus_per_node > 0:
                 tasks_per_node = min(
                     self.get_value("MAX_TASKS_PER_NODE") // max_thread_count,
                     self.get_value("MAX_CPUTASKS_PER_GPU_NODE"),