diff --git a/lca_carbon_workflow.py b/lca_carbon_workflow.py
index e9a09ff..f804757 100644
--- a/lca_carbon_workflow.py
+++ b/lca_carbon_workflow.py
@@ -118,7 +118,8 @@ class LCACarbonWorkflow:
          self.nrcan_catalogs.search_materials(layer.material_name)
         layer_emission.append(EnvelopeEmission(
           layer_material['embodied_carbon'],
-          boundary.opaque_area, layer.thickness).calculate_envelope_emission())
+          boundary.opaque_area,
+          layer.thickness, layer.density).calculate_envelope_emission())
         boundary_workload.append(
           boundary.opaque_area * layer.thickness * layer.density)
     return layer_emission, boundary_workload