diff --git a/tubelib/command.lua b/tubelib/command.lua
index 4942897..96acd40 100644
--- a/tubelib/command.lua
+++ b/tubelib/command.lua
@@ -431,6 +431,14 @@ end
 function tubelib.push_items(pos, side, items, player_name)
 	local npos, nside, name = get_dest_node(pos, side)
 	if npos == nil then return end
+
+	local _,node = Tube:get_node(pos)
+	local dir = side_to_dir(side, node.param2)
+	local node, _, valid = Tube:get_secondary_node(pos, dir)
+	if node and not valid then
+		return false
+	end
+
 	if tubelib_NodeDef[name] and tubelib_NodeDef[name].on_push_item then
 		return tubelib_NodeDef[name].on_push_item(npos, nside, items, player_name)
 	elseif name == "air" then