diff --git a/lca_carbon_workflow.py b/lca_carbon_workflow.py
index a510ca3..e9a09ff 100644
--- a/lca_carbon_workflow.py
+++ b/lca_carbon_workflow.py
@@ -120,7 +120,7 @@ class LCACarbonWorkflow:
           layer_material['embodied_carbon'],
           boundary.opaque_area, layer.thickness).calculate_envelope_emission())
         boundary_workload.append(
-          boundary.opaque_area * layer.thickness * layer_material['density'])
+          boundary.opaque_area * layer.thickness * layer.density)
     return layer_emission, boundary_workload
 
   def _calculate_opening_emission(