diff --git a/source/materials/OpticalMaterialProperties.cc b/source/materials/OpticalMaterialProperties.cc
index 7813a346e2..3d2664b995 100644
--- a/source/materials/OpticalMaterialProperties.cc
+++ b/source/materials/OpticalMaterialProperties.cc
@@ -1439,7 +1439,7 @@ namespace opticalprops {
     float minAbsLength = 0.395 * mm;
 
     std::vector<float> B2_absorption {
-      -0.01         // 418
+      -0.01,        // 418
       -0.06, -0.26, // 405, 412
       -0.44, -0.59, // 394, 400
       -0.59, -0.64, // 384, 387