diff --git a/umich_catalog_indexing/lib/ht_traject/ht_hathifiles.rb b/umich_catalog_indexing/lib/ht_traject/ht_hathifiles.rb
index e5cdf10b..89b0aad5 100644
--- a/umich_catalog_indexing/lib/ht_traject/ht_hathifiles.rb
+++ b/umich_catalog_indexing/lib/ht_traject/ht_hathifiles.rb
@@ -47,7 +47,9 @@ def self.get_hf_info(oclc_nums, bib_nums)
 
       query(bib_nums: bib_nums, oclc_nums: oclc_nums).each do |r|
         hf_hash[r[:id]] = r
-        hf_hash[r[:id]]["source"] = CGI.unescapeHTML(CC_TO_OF[r[:collection_code].downcase])
+        collection_code = CC_TO_OF[r[:collection_code].downcase]
+        raise StandardError, "HathiTrust collection code not found: #{r[:collection_code]}" if collection_code.nil?
+        hf_hash[r[:id]]["source"] = CGI.unescapeHTML(collection_code)
       end
 
       hf_hash.values
diff --git a/umich_catalog_indexing/lib/translation_maps/ht/collection_code_to_original_from.yaml b/umich_catalog_indexing/lib/translation_maps/ht/collection_code_to_original_from.yaml
index ff37466a..7c3e5b64 100644
--- a/umich_catalog_indexing/lib/translation_maps/ht/collection_code_to_original_from.yaml
+++ b/umich_catalog_indexing/lib/translation_maps/ht/collection_code_to_original_from.yaml
@@ -53,6 +53,7 @@ nnfr: The Frick Collection
 nrlf: University of California
 nwu: Northwestern University
 nyp: New York Public Library
+oclw: Case Western Reserve University
 oks: Oklahoma State University
 osu: The Ohio State University
 phc: Haverford College