diff --git a/nix-store-receipt.py b/nix-store-receipt.py
index ace208a..6141de8 100755
--- a/nix-store-receipt.py
+++ b/nix-store-receipt.py
@@ -7,7 +7,7 @@ import sys
 
 def get_closure(installables):
     closure = subprocess.run(
-        ["nix", "path-info", "--recursive"] + installables,
+        ["nix", "path-info", "--recursive", "--impure"] + installables,
         encoding="utf8",
         stdout=subprocess.PIPE,
     )