diff --git a/backend/model/reftracker_mapper.rb b/backend/model/reftracker_mapper.rb
index e1e78e8..16ab2db 100644
--- a/backend/model/reftracker_mapper.rb
+++ b/backend/model/reftracker_mapper.rb
@@ -117,7 +117,7 @@ def self.map_accession(qp, agent_uri, subject_uris)
 
     acc['id_0'] = qp['bib_udf_tb03']
 
-    acc['accession_date'] = qp['question_closed_datetime'].split[0]
+    acc['accession_date'] = qp.fetch('question_closed_datetime', '').split[0]
 
     acc['acquisition_type'] = qp['question_udf_cl03'].downcase
     acc['content_description'] = qp['question_udf_ta08'] || qp['question_text']