diff --git a/opm/parser/eclipse/EclipseState/Tables/TLMixpar.hpp b/opm/parser/eclipse/EclipseState/Tables/TLMixpar.hpp
index 9f40f2707..640d23dd5 100644
--- a/opm/parser/eclipse/EclipseState/Tables/TLMixpar.hpp
+++ b/opm/parser/eclipse/EclipseState/Tables/TLMixpar.hpp
@@ -56,7 +56,7 @@ class TLMixpar {
 public:
 
     TLMixpar() = default;
-    TLMixpar(const Deck& deck);
+    explicit TLMixpar(const Deck& deck);
     static TLMixpar serializeObject();
     std::size_t size() const;
     bool empty() const;