diff --git a/DataFormats/Detectors/EMCAL/include/DataFormatsEMCAL/CellLabel.h b/DataFormats/Detectors/EMCAL/include/DataFormatsEMCAL/CellLabel.h
index 0bba3a02e3f35..401bbf57c2af0 100644
--- a/DataFormats/Detectors/EMCAL/include/DataFormatsEMCAL/CellLabel.h
+++ b/DataFormats/Detectors/EMCAL/include/DataFormatsEMCAL/CellLabel.h
@@ -43,7 +43,7 @@ class CellLabel
   /// \brief Constructor using gsl::span
   /// \param labels list of mc labels
   /// \param amplitudeFractions list of amplitude fractions
-  CellLabel(std::vector<int> labels, std::vector<float> amplitudeFractions);
+  CellLabel(gsl::span<const int> labels, gsl::span<const float> amplitudeFractions);
 
   // ~CellLabel() = default;
   // CellLabel(const CellLabel& clus) = default;
@@ -77,4 +77,4 @@ class CellLabel
 
 } // namespace emcal
 } // namespace o2
-#endif // ALICEO2_EMCAL_CELLLABEL_H_
+#endif // ALICEO2_EMCAL_CELLLABEL_H_
\ No newline at end of file
diff --git a/DataFormats/Detectors/EMCAL/src/CellLabel.cxx b/DataFormats/Detectors/EMCAL/src/CellLabel.cxx
index cbc1c2897520a..8a2a5d5a0a0a0 100644
--- a/DataFormats/Detectors/EMCAL/src/CellLabel.cxx
+++ b/DataFormats/Detectors/EMCAL/src/CellLabel.cxx
@@ -15,14 +15,20 @@
 #include "fairlogger/Logger.h"
 #include <cstddef>
 #include <cstdint>
-#include <vector>
 #include <gsl/span>
 #include <vector>
 #include <utility>
 
 using namespace o2::emcal;
 
-CellLabel::CellLabel(std::vector<int> labels, std::vector<float> amplitudeFractions) : mLabels(labels), mAmplitudeFraction(amplitudeFractions)
+CellLabel::CellLabel(std::vector<int> labels, std::vector<float> amplitudeFractions) : mLabels(std::move(labels)), mAmplitudeFraction(std::move(amplitudeFractions))
+{
+  if (labels.size() != amplitudeFractions.size()) {
+    LOG(error) << "Size of labels " << labels.size() << " does not match size of amplitude fraction " << amplitudeFractions.size() << " !";
+  }
+}
+
+CellLabel::CellLabel(gsl::span<const int> labels, gsl::span<const float> amplitudeFractions) : mLabels(labels.begin(), labels.end()), mAmplitudeFraction(amplitudeFractions.begin(), amplitudeFractions.end())
 {
   if (labels.size() != amplitudeFractions.size()) {
     LOG(error) << "Size of labels " << labels.size() << " does not match size of amplitude fraction " << amplitudeFractions.size() << " !";
@@ -41,4 +47,4 @@ int32_t CellLabel::GetLeadingMCLabel() const
     }
   }
   return mLabels[maxIndex];
-}
+}
\ No newline at end of file