diff --git a/SimCalorimetry/EcalTrigPrimProducers/plugins/EcalTrigPrimESProducer.cc b/SimCalorimetry/EcalTrigPrimProducers/plugins/EcalTrigPrimESProducer.cc
index ca3437544de7c..b8ae5c2fe4a65 100644
--- a/SimCalorimetry/EcalTrigPrimProducers/plugins/EcalTrigPrimESProducer.cc
+++ b/SimCalorimetry/EcalTrigPrimProducers/plugins/EcalTrigPrimESProducer.cc
@@ -43,7 +43,7 @@ struct GzInputStream
    { gzclose(gzf) ; }
   explicit operator bool() const
   {
-    return ((eof == true) ? false : iss.fail());
+    return ((eof == true) ? false : !iss.fail());
   }
  } ;