diff --git a/TileEngine/LightEffects.h b/TileEngine/LightEffects.h
index b11dfe29..2be95ded 100644
--- a/TileEngine/LightEffects.h
+++ b/TileEngine/LightEffects.h
@@ -17,7 +17,7 @@ typedef struct
 
 	UINT8		ubDuration;		       // the number of turns will remain effective
 	UINT8		bRadius;	          // the current radius
-	INT8		bAge;				        // the number of turns light has been around
+	UINT8		bAge;				        // the number of turns light has been around
 	BOOLEAN	fAllocated;
 	INT32		iLight;
 	UINT32	uiTimeOfLastUpdate;
diff --git a/TileEngine/SmokeEffects.h b/TileEngine/SmokeEffects.h
index d2ddd5e2..07d1036e 100644
--- a/TileEngine/SmokeEffects.h
+++ b/TileEngine/SmokeEffects.h
@@ -25,7 +25,7 @@ typedef struct TAG_SMOKE_EFFECT
 	UINT8		ubDuration;        // the number of turns gas will remain effective
 	UINT8		ubRadius;          // the current radius of the cloud in map tiles
 	UINT8   bFlags;            // 0 - outdoors (fast spread), 1 - indoors (slow)
-	INT8		bAge;             // the number of turns gas has been around
+	UINT8		bAge;             // the number of turns gas has been around
 	BOOLEAN	fAllocated;
 	INT8		bType;
 	UINT16	usItem;