Index: src/industry_cmd.cpp
===================================================================
--- src/industry_cmd.cpp	(revision 27171)
+++ src/industry_cmd.cpp	(working copy)
@@ -1756,8 +1756,13 @@
 
 			WaterClass wc = (IsWaterTile(cur_tile) ? GetWaterClass(cur_tile) : WATER_CLASS_INVALID);
 
+			/* While it's true Industry Tiles don't have any owner, the following
+			DoCommand below is inadvertently setting bit 4 of m1 to 1. To preserve its
+			original value, store it first before executing DoCommand, then restore it
+			before MakeIndustry takes action. */
+			Owner old_owner = GetTileOwner(cur_tile); 
 			DoCommand(cur_tile, 0, 0, DC_EXEC | DC_NO_TEST_TOWN_RATING | DC_NO_MODIFY_TOWN_RATING, CMD_LANDSCAPE_CLEAR);
-
+			SetTileOwner(cur_tile, old_owner);
 			MakeIndustry(cur_tile, i->index, it->gfx, Random(), wc);
 
 			if (_generating_world) {
Index: src/industry_map.h
===================================================================
--- src/industry_map.h	(revision 27171)
+++ src/industry_map.h	(working copy)
@@ -280,7 +280,7 @@
 static inline void MakeIndustry(TileIndex t, IndustryID index, IndustryGfx gfx, uint8 random, WaterClass wc)
 {
 	SetTileType(t, MP_INDUSTRY);
-	_m[t].m1 = 0;
+	_m[t].m1 &= 1<<4; // Make sure bit 4 is unaffected.
 	_m[t].m2 = index;
 	SetIndustryRandomBits(t, random); // m3
 	_m[t].m4 = 0;
Index: src/saveload/afterload.cpp
===================================================================
--- src/saveload/afterload.cpp	(revision 27171)
+++ src/saveload/afterload.cpp	(working copy)
@@ -2985,6 +2985,16 @@
 	ResetSignalHandlers();
 
 	AfterLoadLinkGraphs();
+
+	/* Convert m1 bit 4 value for all industry tiles */
+	for (TileIndex t = 0; t < map_size; t++) {
+		/* It's not possible to know who was the original owner of a canal tile built under
+		an Oil Rig tile from an old save game. To preserve savegame backward compatibility,
+		don't do anything about them. Old and new values for a given industry tile can co-exist. */
+		if (IsTileType(t, MP_INDUSTRY) && (GetWaterClass(t) != WATER_CLASS_CANAL)) {
+			SB(_m[t].m1, 4, 1, 1);
+		}
+	}
 	return true;
 }