diff --git a/source/f90/seteps.f90 b/source/f90/seteps.f90
index 72fa34b26c07c79159c07bbdf1332ae3c04b7c57..6ae2fc11c9762187db5b512e97d3b6f70b772de4 100644
--- a/source/f90/seteps.f90
+++ b/source/f90/seteps.f90
@@ -78,6 +78,8 @@ subroutine seteps(neps, nos, osc, epsinf, wn, name, eps, layers, mode)
           deno = 1.0d0 - deno
         endif
         if (cdabs(deno) == 0.0d0) then ! replace 0 by machine epsilon
+          ! if deno is always > 0 then this would do it: 
+          ! deno = cdmax(deno, epsilon(1.0d0) / 2)
           deno = epsilon(1.0d0) / 2
         endif
         eps(l) = eps(l) + osc(2, j) / deno