diff --git a/src/micropolisj/engine/TileConstants.java b/src/micropolisj/engine/TileConstants.java
index 1bea777..8afcd76 100644
--- a/src/micropolisj/engine/TileConstants.java
+++ b/src/micropolisj/engine/TileConstants.java
@@ -662,6 +662,11 @@ public class TileConstants
 			(tile & LOMASK) < COMBASE;
 	}
 
+	/**
+	 * Checks whether the tile is defined with the "industrial-zone" attribute.
+	 * Note: the old version of this function erroneously included the coal power
+	 * plant smoke as an industrial zone.
+	 */
 	public static boolean isIndustrialZone(int tile)
 	{
 		int tmp = tile & LOMASK;
@@ -675,14 +680,6 @@ public class TileConstants
 		return false;
 	}
 
-	public static boolean isIndustrialZoneOld(int tile)
-	{
-		int tmp = tile & LOMASK;
-		return (tmp >= INDBASE && tmp < PORTBASE)
-		|| (tmp >= SMOKEBASE && tmp < TINYEXP)
-		|| (tmp >= SMOKEBASE2 && tmp < FOOTBALLGAME1);
-	}
-
 	public static boolean isResidentialClear(int tile)
 	{
 		return (tile & LOMASK) >= RESBASE && (tile & LOMASK) <= RESBASE+8;
diff --git a/src/micropolisj/engine/Tiles.java b/src/micropolisj/engine/Tiles.java
index aeeb55d..db334f6 100644
--- a/src/micropolisj/engine/Tiles.java
+++ b/src/micropolisj/engine/Tiles.java
@@ -105,9 +105,7 @@ public class Tiles
 	static void checkTiles()
 	{
 		for (int i = 0; i < tiles.length; i++) {
-			if (TileConstants.isIndustrialZone(i) != TileConstants.isIndustrialZoneOld(i)) {
-				System.err.println("industrial zone disagreement: "+i);
-			}
+			// do something here
 		}
 	}
 }