diff --git a/lib/googleauth/credentials_loader.rb b/lib/googleauth/credentials_loader.rb
index 5ecda5d2..9c92f4b9 100644
--- a/lib/googleauth/credentials_loader.rb
+++ b/lib/googleauth/credentials_loader.rb
@@ -175,7 +175,7 @@ def warn_if_cloud_sdk_credentials client_id
       def load_gcloud_project_id
         gcloud = GCLOUD_WINDOWS_COMMAND if OS.windows?
         gcloud = GCLOUD_POSIX_COMMAND unless OS.windows?
-        gcloud_json = IO.popen("#{gcloud} #{GCLOUD_CONFIG_COMMAND}", &:read)
+        gcloud_json = IO.popen("#{gcloud} #{GCLOUD_CONFIG_COMMAND}", in: :close, err: :close, &:read)
         config = MultiJson.load gcloud_json
         config["configuration"]["properties"]["core"]["project"]
       rescue StandardError