diff --git a/activestorage/netcdf_to_zarr.py b/activestorage/netcdf_to_zarr.py
index 9c7cc75e..214b47af 100644
--- a/activestorage/netcdf_to_zarr.py
+++ b/activestorage/netcdf_to_zarr.py
@@ -81,6 +81,7 @@ def _load_ds(s3file_o_1, varname):
         s3file = s3file_r_1[varname]
 
     s3file_r_1.close()
+    s3file_w_1.close()
 
     return s3file