diff --git a/ai-compliance-sdk/internal/api/handlers/iace_handler_init.go b/ai-compliance-sdk/internal/api/handlers/iace_handler_init.go
index a6cda39..6d695b7 100644
--- a/ai-compliance-sdk/internal/api/handlers/iace_handler_init.go
+++ b/ai-compliance-sdk/internal/api/handlers/iace_handler_init.go
@@ -140,13 +140,21 @@ func (h *IACEHandler) InitializeProject(c *gin.Context) {
 					name = cat
 				}
 				scenario := mp.ScenarioDE
+				hazardType := mp.GeneratedHazardType
+				if hazardType == "" {
+					hazardType = iace.DefaultHazardType
+				}
 				hz, cerr := h.store.CreateHazard(ctx, iace.CreateHazardRequest{
-					ProjectID:   projectID,
-					ComponentID: defaultCompID,
-					Name:        name,
-					Description: scenario,
-					Category:    cat,
-					Scenario:    scenario,
+					ProjectID:      projectID,
+					ComponentID:    defaultCompID,
+					Name:           name,
+					Description:    scenario,
+					Category:       cat,
+					Scenario:       scenario,
+					TriggerEvent:   mp.TriggerDE,
+					PossibleHarm:   mp.HarmDE,
+					AffectedPerson: mp.AffectedDE,
+					HazardousZone:  mp.ZoneDE,
 				})
 				if cerr == nil {
 					created++
diff --git a/ai-compliance-sdk/internal/iace/hazard_pattern_types.go b/ai-compliance-sdk/internal/iace/hazard_pattern_types.go
index 58b825e..5c4ad74 100644
--- a/ai-compliance-sdk/internal/iace/hazard_pattern_types.go
+++ b/ai-compliance-sdk/internal/iace/hazard_pattern_types.go
@@ -46,6 +46,10 @@ type HazardPattern struct {
 	// interact with the machine. Empty/nil = fires for all roles (backwards compatible).
 	// Standard roles: operator, maintenance_tech, programmer, cleaning_staff, bystander, supervisor.
 	HumanRoles []string `json:"human_roles,omitempty"`
+	// GeneratedHazardType sets the ISO 12100 type for hazards created by this pattern.
+	// "hazard" = source only, "hazardous_situation" = person exposed, "harm" = injury.
+	// Empty = default (hazardous_situation).
+	GeneratedHazardType string `json:"generated_hazard_type,omitempty"`
 }
 
 // Standard human roles for machinery interaction (ISO 12100 + BetrSichV).
diff --git a/ai-compliance-sdk/internal/iace/models.go b/ai-compliance-sdk/internal/iace/models.go
index f596e12..fc58b94 100644
--- a/ai-compliance-sdk/internal/iace/models.go
+++ b/ai-compliance-sdk/internal/iace/models.go
@@ -57,6 +57,37 @@ const (
 	HazardStatusClosed     HazardStatus = "closed"
 )
 
+// HazardType distinguishes ISO 12100 concepts in the hazard chain:
+// Hazard → Hazardous Situation → Harm
+const (
+	HazardTypeHazard             = "hazard"             // Source of potential harm (e.g. rotating shaft)
+	HazardTypeHazardousSituation = "hazardous_situation" // Person exposed to hazard (e.g. operator near shaft)
+	HazardTypeHarm               = "harm"               // Injury outcome (e.g. entanglement)
+	DefaultHazardType            = HazardTypeHazardousSituation
+)
+
+// DeriveHazardType determines the ISO 12100 hazard type from the hazard's fields.
+// If an explicit type is set, it is returned as-is. Otherwise:
+//   - PossibleHarm filled + Scenario filled → "hazardous_situation" (most specific)
+//   - Only PossibleHarm filled → "harm"
+//   - Only TriggerEvent/Category → "hazard" (source only)
+//   - Default fallback → "hazardous_situation"
+func DeriveHazardType(h *Hazard) string {
+	if h.HazardType != "" {
+		return h.HazardType
+	}
+	if h.Scenario != "" && h.PossibleHarm != "" {
+		return HazardTypeHazardousSituation
+	}
+	if h.PossibleHarm != "" && h.Scenario == "" {
+		return HazardTypeHarm
+	}
+	if h.Scenario == "" && h.PossibleHarm == "" && h.Category != "" {
+		return HazardTypeHazard
+	}
+	return DefaultHazardType
+}
+
 // AssessmentType represents the type of risk assessment
 type AssessmentType string
 
diff --git a/ai-compliance-sdk/internal/iace/models_entities.go b/ai-compliance-sdk/internal/iace/models_entities.go
index 0c304a7..e0b30da 100644
--- a/ai-compliance-sdk/internal/iace/models_entities.go
+++ b/ai-compliance-sdk/internal/iace/models_entities.go
@@ -111,6 +111,12 @@ type Hazard struct {
 	TriggerEvent    string       `json:"trigger_event,omitempty"`
 	AffectedPerson  string       `json:"affected_person,omitempty"`
 	PossibleHarm    string       `json:"possible_harm,omitempty"`
+	// HazardType distinguishes ISO 12100 concepts:
+	//   "hazard"              — the source of potential harm (e.g. mechanical movement)
+	//   "hazardous_situation"  — person exposed to hazard (e.g. person in motion range)
+	//   "harm"                — the injury outcome (e.g. crushing)
+	// Derived field — not stored in DB. Computed by DeriveHazardType().
+	HazardType      string       `json:"hazard_type,omitempty"`
 	ReviewStatus    ReviewStatus `json:"review_status,omitempty"`
 	CreatedAt       time.Time    `json:"created_at"`
 	UpdatedAt       time.Time    `json:"updated_at"`
diff --git a/ai-compliance-sdk/internal/iace/pattern_engine.go b/ai-compliance-sdk/internal/iace/pattern_engine.go
index 95007f0..1c8aef0 100644
--- a/ai-compliance-sdk/internal/iace/pattern_engine.go
+++ b/ai-compliance-sdk/internal/iace/pattern_engine.go
@@ -56,7 +56,8 @@ type PatternMatch struct {
 	RequiresExpert    bool     `json:"requires_expert,omitempty"`
 	OperationalStates []string `json:"operational_states,omitempty"`
 	StateTransitions  []string `json:"state_transitions,omitempty"`
-	HumanRoles        []string `json:"human_roles,omitempty"`
+	HumanRoles          []string `json:"human_roles,omitempty"`
+	GeneratedHazardType string   `json:"generated_hazard_type,omitempty"`
 }
 
 // HazardSuggestion is a suggested hazard from pattern matching.
@@ -225,9 +226,10 @@ func (e *PatternEngine) Match(input MatchInput) *MatchOutput {
 			HazardCats:      p.GeneratedHazardCats,
 			ExpertHintDE:      p.ExpertHintDE,
 			RequiresExpert:    p.RequiresExpertCalculation,
-			OperationalStates: p.OperationalStates,
-			StateTransitions:  p.StateTransitions,
-			HumanRoles:        p.HumanRoles,
+			OperationalStates:   p.OperationalStates,
+			StateTransitions:    p.StateTransitions,
+			HumanRoles:          p.HumanRoles,
+			GeneratedHazardType: p.GeneratedHazardType,
 		})
 
 		for _, cat := range p.GeneratedHazardCats {
diff --git a/ai-compliance-sdk/internal/iace/phase3_4_test.go b/ai-compliance-sdk/internal/iace/phase3_4_test.go
index 1fcd031..ba09af1 100644
--- a/ai-compliance-sdk/internal/iace/phase3_4_test.go
+++ b/ai-compliance-sdk/internal/iace/phase3_4_test.go
@@ -338,6 +338,62 @@ func TestEvidenceTypes_UniqueIDs(t *testing.T) {
 	}
 }
 
+// ══════════════════════════════════════════════════════════════════
+// Sprint 4B: HazardType / ISO 12100 Trennung
+// ══════════════════════════════════════════════════════════════════
+
+func TestDeriveHazardType_WithScenarioAndHarm(t *testing.T) {
+	h := &Hazard{Scenario: "Person im Bewegungsraum", PossibleHarm: "Quetschung"}
+	if got := DeriveHazardType(h); got != HazardTypeHazardousSituation {
+		t.Errorf("expected hazardous_situation, got %s", got)
+	}
+}
+
+func TestDeriveHazardType_HarmOnly(t *testing.T) {
+	h := &Hazard{PossibleHarm: "Quetschung", Category: "mechanical"}
+	if got := DeriveHazardType(h); got != HazardTypeHarm {
+		t.Errorf("expected harm, got %s", got)
+	}
+}
+
+func TestDeriveHazardType_CategoryOnly(t *testing.T) {
+	h := &Hazard{Category: "mechanical_hazard"}
+	if got := DeriveHazardType(h); got != HazardTypeHazard {
+		t.Errorf("expected hazard, got %s", got)
+	}
+}
+
+func TestDeriveHazardType_ExplicitOverride(t *testing.T) {
+	h := &Hazard{HazardType: "harm", Scenario: "ignored", PossibleHarm: "ignored"}
+	if got := DeriveHazardType(h); got != "harm" {
+		t.Errorf("expected explicit harm, got %s", got)
+	}
+}
+
+func TestDeriveHazardType_EmptyFallback(t *testing.T) {
+	h := &Hazard{}
+	if got := DeriveHazardType(h); got != DefaultHazardType {
+		t.Errorf("expected default %s, got %s", DefaultHazardType, got)
+	}
+}
+
+func TestPatternMatch_GeneratedHazardType(t *testing.T) {
+	// Verify PatternMatch carries GeneratedHazardType
+	engine := NewPatternEngine()
+	result := engine.Match(MatchInput{
+		ComponentLibraryIDs: []string{"C001"},
+		EnergySourceIDs:     []string{"EN01"},
+	})
+	// Most patterns don't set GeneratedHazardType (empty = default)
+	// Just verify the field exists and doesn't crash
+	for _, p := range result.MatchedPatterns {
+		_ = p.GeneratedHazardType // Should compile and not panic
+	}
+	if len(result.MatchedPatterns) == 0 {
+		t.Fatal("expected matched patterns")
+	}
+}
+
 func TestEvidenceTypes_SortOrder(t *testing.T) {
 	types := GetEvidenceTypeLibrary()
 	for i := 1; i < len(types); i++ {
diff --git a/ai-compliance-sdk/internal/iace/store_hazards.go b/ai-compliance-sdk/internal/iace/store_hazards.go
index 67af66e..c6b6336 100644
--- a/ai-compliance-sdk/internal/iace/store_hazards.go
+++ b/ai-compliance-sdk/internal/iace/store_hazards.go
@@ -95,6 +95,7 @@ func (s *Store) GetHazard(ctx context.Context, id uuid.UUID) (*Hazard, error) {
 
 	h.Status = HazardStatus(status)
 	h.ReviewStatus = ReviewStatus(reviewStatus)
+	h.HazardType = DeriveHazardType(&h)
 	return &h, nil
 }
 
@@ -133,6 +134,7 @@ func (s *Store) ListHazards(ctx context.Context, projectID uuid.UUID) ([]Hazard,
 
 		h.Status = HazardStatus(status)
 		h.ReviewStatus = ReviewStatus(reviewStatus)
+		h.HazardType = DeriveHazardType(&h)
 		hazards = append(hazards, h)
 	}