diff --git a/pangeo_forge_recipes/transforms.py b/pangeo_forge_recipes/transforms.py
index 160ad1a6..d64af2ed 100644
--- a/pangeo_forge_recipes/transforms.py
+++ b/pangeo_forge_recipes/transforms.py
@@ -147,12 +147,16 @@ class TransferFilesWithConcurrency(beam.DoFn):
         concurrency_per_executor: The number of concurrent threads per executor.
         secrets: Optional dictionary containing secrets required for accessing the transfer target.
         open_kwargs: Optional dictionary of keyword arguments to be passed when opening files.
+        fsspec_sync_patch: Experimental. Likely slower. When enabled, this attempts to
+            replace asynchronous code with synchronous implementations to potentially address
+            deadlocking issues. cf. https://github.com/h5py/h5py/issues/2019
     """
 
     transfer_target: CacheFSSpecTarget
     max_concurrency: int
     secrets: Optional[Dict] = None
     open_kwargs: Optional[Dict] = None
+    fsspec_sync_patch: bool = False
 
     def process(self, indexed_urls):
         with ThreadPoolExecutor(max_workers=self.max_concurrency) as executor:
@@ -170,7 +174,7 @@ def process(self, indexed_urls):
 
     def transfer_file(self, index: Index, url: str) -> Tuple[Index, str]:
         open_kwargs = self.open_kwargs or {}
-        self.transfer_target.cache_file(url, self.secrets, **open_kwargs)
+        self.transfer_target.cache_file(url, self.secrets, self.fsspec_sync_patch, **open_kwargs)
         return (index, self.transfer_target._full_path(url))
 
 
@@ -188,6 +192,9 @@ class CheckpointFileTransfer(beam.PTransform):
             number to limit total cluster concurrency. Default is 20.
         concurrency_per_executor (Optional[int]): The number of concurrent threads per executor.
             Default is 10.
+        fsspec_sync_patch: Experimental. Likely slower. When enabled, this attempts to
+            replace asynchronous code with synchronous implementations to potentially address
+            deadlocking issues. cf. https://github.com/h5py/h5py/issues/2019
     """
 
     transfer_target: Union[str, CacheFSSpecTarget]
@@ -195,6 +202,7 @@ class CheckpointFileTransfer(beam.PTransform):
     open_kwargs: Optional[dict] = None
     max_executors: int = 20
     concurrency_per_executor: int = 10
+    fsspec_sync_patch: bool = False
 
     def assign_keys(self, element) -> Tuple[int, Any]:
         index, url = element
@@ -219,6 +227,7 @@ def expand(self, pcoll):
                     secrets=self.secrets,
                     open_kwargs=self.open_kwargs,
                     max_concurrency=self.concurrency_per_executor,
+                    fsspec_sync_patch=self.fsspec_sync_patch,
                 )
             )
         )