diff --git a/src/storm/builder/ExplicitModelBuilder.cpp b/src/storm/builder/ExplicitModelBuilder.cpp
index d6096e750..ac4b554d5 100644
--- a/src/storm/builder/ExplicitModelBuilder.cpp
+++ b/src/storm/builder/ExplicitModelBuilder.cpp
@@ -89,20 +89,22 @@ namespace storm {
             // Check, if the state was already registered.
             std::pair<StateType, std::size_t> actualIndexBucketPair = stateStorage.stateToId.findOrAddAndGetBucket(state, newIndex);
             
-            if (actualIndexBucketPair.first == newIndex) {
+            StateType actualIndex = actualIndexBucketPair.first;
+            
+            if (actualIndex == newIndex) {
                 if (options.explorationOrder == ExplorationOrder::Dfs) {
-                    statesToExplore.emplace_front(state, actualIndexBucketPair.first);
+                    statesToExplore.emplace_front(state, actualIndex);
 
                     // Reserve one slot for the new state in the remapping.
                     stateRemapping.get().push_back(storm::utility::zero<StateType>());
                 } else if (options.explorationOrder == ExplorationOrder::Bfs) {
-                    statesToExplore.emplace_back(state, actualIndexBucketPair.first);
+                    statesToExplore.emplace_back(state, actualIndex);
                 } else {
                     STORM_LOG_ASSERT(false, "Invalid exploration order.");
                 }
             }
             
-            return actualIndexBucketPair.first;
+            return actualIndex;
         }
         
         template <typename ValueType, typename RewardModelType, typename StateType>
@@ -306,7 +308,7 @@ namespace storm {
             
             buildMatrices(transitionMatrixBuilder, rewardModelBuilders, choiceInformationBuilder, markovianStates);
             
-            // initialize the model components with the obtained information.
+            // Initialize the model components with the obtained information.
             storm::storage::sparse::ModelComponents<ValueType, RewardModelType> modelComponents(transitionMatrixBuilder.build(), buildStateLabeling(), std::unordered_map<std::string, RewardModelType>(), !generator->isDiscreteTimeModel(), std::move(markovianStates));
             
             // Now finalize all reward models.
@@ -316,7 +318,7 @@ namespace storm {
             // Build the choice labeling
             modelComponents.choiceLabeling = choiceInformationBuilder.buildChoiceLabeling(modelComponents.transitionMatrix.getRowCount());
             
-            // if requested, build the state valuations and choice origins
+            // If requested, build the state valuations and choice origins
             if (generator->getOptions().isBuildStateValuationsSet()) {
                 std::vector<storm::expressions::SimpleValuation> valuations(modelComponents.transitionMatrix.getRowGroupCount());
                 for (auto const& bitVectorIndexPair : stateStorage.stateToId) {
@@ -334,7 +336,7 @@ namespace storm {
         
         template <typename ValueType, typename RewardModelType, typename StateType>
         storm::models::sparse::StateLabeling ExplicitModelBuilder<ValueType, RewardModelType, StateType>::buildStateLabeling() {
-            return generator->label(stateStorage.stateToId, stateStorage.initialStateIndices, stateStorage.deadlockStateIndices);
+            return generator->label(stateStorage, stateStorage.initialStateIndices, stateStorage.deadlockStateIndices);
         }
         
         // Explicitly instantiate the class.
diff --git a/src/storm/generator/JaniNextStateGenerator.cpp b/src/storm/generator/JaniNextStateGenerator.cpp
index f7d86e914..40481fd83 100644
--- a/src/storm/generator/JaniNextStateGenerator.cpp
+++ b/src/storm/generator/JaniNextStateGenerator.cpp
@@ -608,7 +608,7 @@ namespace storm {
         }
         
         template<typename ValueType, typename StateType>
-        storm::models::sparse::StateLabeling JaniNextStateGenerator<ValueType, StateType>::label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices) {
+        storm::models::sparse::StateLabeling JaniNextStateGenerator<ValueType, StateType>::label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices) {
             // As in JANI we can use transient boolean variable assignments in locations to identify states, we need to
             // create a list of boolean transient variables and the expressions that define them.
             std::unordered_map<storm::expressions::Variable, storm::expressions::Expression> transientVariableToExpressionMap;
@@ -625,7 +625,7 @@ namespace storm {
                 transientVariableExpressions.push_back(std::make_pair(element.first.getName(), element.second));
             }
             
-            return NextStateGenerator<ValueType, StateType>::label(states, initialStateIndices, deadlockStateIndices, transientVariableExpressions);
+            return NextStateGenerator<ValueType, StateType>::label(stateStorage, initialStateIndices, deadlockStateIndices, transientVariableExpressions);
         }
         
         template<typename ValueType, typename StateType>
diff --git a/src/storm/generator/JaniNextStateGenerator.h b/src/storm/generator/JaniNextStateGenerator.h
index 3fcfc2777..594efc91c 100644
--- a/src/storm/generator/JaniNextStateGenerator.h
+++ b/src/storm/generator/JaniNextStateGenerator.h
@@ -30,7 +30,7 @@ namespace storm {
             virtual std::size_t getNumberOfRewardModels() const override;
             virtual storm::builder::RewardModelInformation getRewardModelInformation(uint64_t const& index) const override;
                         
-            virtual storm::models::sparse::StateLabeling label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices = {}, std::vector<StateType> const& deadlockStateIndices = {}) override;
+            virtual storm::models::sparse::StateLabeling label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices = {}, std::vector<StateType> const& deadlockStateIndices = {}) override;
             
         private:
             /*!
diff --git a/src/storm/generator/NextStateGenerator.cpp b/src/storm/generator/NextStateGenerator.cpp
index 15c6048c3..f69014364 100644
--- a/src/storm/generator/NextStateGenerator.cpp
+++ b/src/storm/generator/NextStateGenerator.cpp
@@ -53,7 +53,7 @@ namespace storm {
         }
         
         template<typename ValueType, typename StateType>
-        storm::models::sparse::StateLabeling NextStateGenerator<ValueType, StateType>::label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices, std::vector<std::pair<std::string, storm::expressions::Expression>> labelsAndExpressions) {
+        storm::models::sparse::StateLabeling NextStateGenerator<ValueType, StateType>::label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices, std::vector<std::pair<std::string, storm::expressions::Expression>> labelsAndExpressions) {
             
             for (auto const& expression : this->options.getExpressionLabels()) {
                 std::stringstream stream;
@@ -67,12 +67,14 @@ namespace storm {
             labelsAndExpressions.resize(std::distance(labelsAndExpressions.begin(), it));
             
             // Prepare result.
-            storm::models::sparse::StateLabeling result(states.size());
+            storm::models::sparse::StateLabeling result(stateStorage.getNumberOfStates());
             
             // Initialize labeling.
             for (auto const& label : labelsAndExpressions) {
                 result.addLabel(label.first);
             }
+            
+            storm::storage::BitVectorHashMap<StateType> const& states = stateStorage.stateToId;
             for (auto const& stateIndexPair : states) {
                 unpackStateIntoEvaluator(stateIndexPair.first, variableInformation, *this->evaluator);
                 
diff --git a/src/storm/generator/NextStateGenerator.h b/src/storm/generator/NextStateGenerator.h
index 25335dbfc..54f7f1024 100644
--- a/src/storm/generator/NextStateGenerator.h
+++ b/src/storm/generator/NextStateGenerator.h
@@ -7,7 +7,7 @@
 #include <boost/variant.hpp>
 
 #include "storm/storage/expressions/Expression.h"
-#include "storm/storage/BitVectorHashMap.h"
+#include "storm/storage/sparse/StateStorage.h"
 #include "storm/storage/expressions/ExpressionEvaluator.h"
 #include "storm/storage/sparse/ChoiceOrigins.h"
 
@@ -61,7 +61,7 @@ namespace storm {
             
             storm::expressions::SimpleValuation toValuation(CompressedState const& state) const;
             
-            virtual storm::models::sparse::StateLabeling label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices = {}, std::vector<StateType> const& deadlockStateIndices = {}) = 0;
+            virtual storm::models::sparse::StateLabeling label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices = {}, std::vector<StateType> const& deadlockStateIndices = {}) = 0;
             
             NextStateGeneratorOptions const& getOptions() const;
             
@@ -71,7 +71,7 @@ namespace storm {
             /*!
              * Creates the state labeling for the given states using the provided labels and expressions.
              */
-            storm::models::sparse::StateLabeling label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices, std::vector<std::pair<std::string, storm::expressions::Expression>> labelsAndExpressions);
+            storm::models::sparse::StateLabeling label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices, std::vector<std::pair<std::string, storm::expressions::Expression>> labelsAndExpressions);
             
             void postprocess(StateBehavior<ValueType, StateType>& result);
             
diff --git a/src/storm/generator/PrismNextStateGenerator.cpp b/src/storm/generator/PrismNextStateGenerator.cpp
index bf9d73876..db74175c0 100644
--- a/src/storm/generator/PrismNextStateGenerator.cpp
+++ b/src/storm/generator/PrismNextStateGenerator.cpp
@@ -575,7 +575,7 @@ namespace storm {
         }
         
         template<typename ValueType, typename StateType>
-        storm::models::sparse::StateLabeling PrismNextStateGenerator<ValueType, StateType>::label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices) {
+        storm::models::sparse::StateLabeling PrismNextStateGenerator<ValueType, StateType>::label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices, std::vector<StateType> const& deadlockStateIndices) {
             // Gather a vector of labels and their expressions.
             std::vector<std::pair<std::string, storm::expressions::Expression>> labels;
             if (this->options.isBuildAllLabelsSet()) {
@@ -592,7 +592,7 @@ namespace storm {
                 }
             }
             
-            return NextStateGenerator<ValueType, StateType>::label(states, initialStateIndices, deadlockStateIndices, labels);
+            return NextStateGenerator<ValueType, StateType>::label(stateStorage, initialStateIndices, deadlockStateIndices, labels);
         }
         
         template<typename ValueType, typename StateType>
diff --git a/src/storm/generator/PrismNextStateGenerator.h b/src/storm/generator/PrismNextStateGenerator.h
index 0097e7055..5cc8ce9ba 100644
--- a/src/storm/generator/PrismNextStateGenerator.h
+++ b/src/storm/generator/PrismNextStateGenerator.h
@@ -28,7 +28,7 @@ namespace storm {
             virtual std::size_t getNumberOfRewardModels() const override;
             virtual storm::builder::RewardModelInformation getRewardModelInformation(uint64_t const& index) const override;
             
-            virtual storm::models::sparse::StateLabeling label(storm::storage::BitVectorHashMap<StateType> const& states, std::vector<StateType> const& initialStateIndices = {}, std::vector<StateType> const& deadlockStateIndices = {}) override;
+            virtual storm::models::sparse::StateLabeling label(storm::storage::sparse::StateStorage<StateType> const& stateStorage, std::vector<StateType> const& initialStateIndices = {}, std::vector<StateType> const& deadlockStateIndices = {}) override;
 
             virtual std::shared_ptr<storm::storage::sparse::ChoiceOrigins> generateChoiceOrigins(std::vector<boost::any>& dataForChoiceOrigins) const override;
 
diff --git a/src/storm/storage/sparse/StateStorage.h b/src/storm/storage/sparse/StateStorage.h
index 789e16c88..65b592cb5 100644
--- a/src/storm/storage/sparse/StateStorage.h
+++ b/src/storm/storage/sparse/StateStorage.h
@@ -27,7 +27,7 @@ namespace storm {
                 // The number of bits of each state.
                 uint64_t bitsPerState;
                 
-                // The number of states that were found in the exploration so far.
+                // Get the number of states that were found in the exploration so far.
                 uint_fast64_t getNumberOfStates() const;
             };