diff --git a/bqskit/passes/search/generators/seed.py b/bqskit/passes/search/generators/seed.py
index 862ee2bc2..03daaf9ec 100644
--- a/bqskit/passes/search/generators/seed.py
+++ b/bqskit/passes/search/generators/seed.py
@@ -168,6 +168,8 @@ def gen_successors(self, circuit: Circuit, data: PassData) -> list[Circuit]:
     def hash_structure(circuit: Circuit) -> int:
         hashes = []
         for cycle, op in circuit.operations_with_cycles():
+            if op.num_qudits <= 1:
+                continue
             hashes.append(hash((cycle, str(op))))
             if len(hashes) > 100:
                 hashes = [sum(hashes)]