diff --git a/doc/fixes36.2 b/doc/fixes36.2
index 51e27582f..ef5053811 100644
--- a/doc/fixes36.2
+++ b/doc/fixes36.2
@@ -142,6 +142,8 @@ known bear trap was being forgotten about by a player polymorphed into a
 no leash-related message is given when a leashed pet yellow light explodes
 shop messages refer to shk by name even when shk is not visible but some
 	used pronoun "it" or "its" in same sentence; ditto for vault guards
+poly'd hero and monsters could eat through iron bars in areas where walls
+	were flagged as non-diggable
 
 
 Fixes to Post-3.6.1 Problems that Were Exposed Via git Repository
diff --git a/include/rm.h b/include/rm.h
index 9d80551db..7fd41c47c 100644
--- a/include/rm.h
+++ b/include/rm.h
@@ -381,7 +381,7 @@ extern struct symsetentry symset[NUM_GRAPHICS]; /* from drawing.c */
 #define DB_UNDER 28 /* mask for underneath */
 
 /*
- * Wall information.
+ * Wall information.  Nondiggable also applies to iron bars.
  */
 #define WM_MASK 0x07 /* wall mode (bottom three bits) */
 #define W_NONDIGGABLE 0x08
diff --git a/src/hack.c b/src/hack.c
index 70671b45f..fabd7e17f 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -364,8 +364,8 @@ moverock()
 /*
  *  still_chewing()
  *
- *  Chew on a wall, door, or boulder.  Returns TRUE if still eating, FALSE
- *  when done.
+ *  Chew on a wall, door, or boulder.  [What about statues?]
+ *  Returns TRUE if still eating, FALSE when done.
  */
 STATIC_OVL int
 still_chewing(x, y)
@@ -379,7 +379,10 @@ xchar x, y;
         (void) memset((genericptr_t) &context.digging, 0,
                       sizeof (struct dig_info));
 
-    if (!boulder && IS_ROCK(lev->typ) && !may_dig(x, y)) {
+    if (!boulder
+        && ((IS_ROCK(lev->typ) && !may_dig(x, y))
+            /* may_dig() checks W_NONDIGGABLE but doesn't handle iron bars */
+            || (lev->typ == IRONBARS && (lev->wall_info & W_NONDIGGABLE)))) {
         You("hurt your teeth on the %s.",
             (lev->typ == IRONBARS)
                 ? "bars"
diff --git a/src/mon.c b/src/mon.c
index 9cdf9b6d9..72f3df1a6 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -1320,7 +1320,11 @@ nexttry: /* eels prefer the water, but if there is no water nearby,
                 && !((IS_TREE(ntyp) ? treeok : rockok) && may_dig(nx, ny)))
                 continue;
             /* KMH -- Added iron bars */
-            if (ntyp == IRONBARS && !(flag & ALLOW_BARS))
+            if (ntyp == IRONBARS
+                && (!(flag & ALLOW_BARS)
+                    || ((levl[nx][ny].wall_info & W_NONDIGGABLE)
+                        && (dmgtype(mdat, AD_RUST)
+                            || dmgtype(mdat, AD_CORR)))))
                 continue;
             if (IS_DOOR(ntyp) && !(amorphous(mdat) || can_fog(mon))
                 && (((levl[nx][ny].doormask & D_CLOSED) && !(flag & OPENDOOR))
diff --git a/src/monmove.c b/src/monmove.c
index 762b4ecb9..fc32ebfb8 100644
--- a/src/monmove.c
+++ b/src/monmove.c
@@ -1388,7 +1388,8 @@ postmov:
                         add_damage(mtmp->mx, mtmp->my, 0L);
                 }
             } else if (levl[mtmp->mx][mtmp->my].typ == IRONBARS) {
-                if (may_dig(mtmp->mx, mtmp->my)
+                /* 3.6.2: was using may_dig() but it doesn't handle bars */
+                if (!(levl[mtmp->mx][mtmp->my].wall_info & W_NONDIGGABLE)
                     && (dmgtype(ptr, AD_RUST) || dmgtype(ptr, AD_CORR))) {
                     if (canseemon(mtmp))
                         pline("%s eats through the iron bars.", Monnam(mtmp));
diff --git a/src/sp_lev.c b/src/sp_lev.c
index 1d6b0cd3a..11d692501 100644
--- a/src/sp_lev.c
+++ b/src/sp_lev.c
@@ -621,6 +621,7 @@ schar filling;
 schar lit;
 {
     int x, y;
+
     for (x = 2; x <= x_maze_max; x++)
         for (y = 0; y <= y_maze_max; y++) {
             SET_TYPLIT(x, y, filling, lit);
@@ -636,11 +637,21 @@ xchar x1, y1, x2, y2;
 int prop;
 {
     register xchar x, y;
+    struct rm *lev;
 
-    for (y = max(y1, 0); y <= min(y2, ROWNO - 1); y++)
-        for (x = max(x1, 0); x <= min(x2, COLNO - 1); x++)
-            if (IS_STWALL(levl[x][y].typ) || IS_TREE(levl[x][y].typ))
-                levl[x][y].wall_info |= prop;
+    x1 = max(x1, 1);
+    x2 = min(x2, COLNO - 1);
+    y1 = max(y1, 0);
+    y2 = min(y2, ROWNO - 1);
+    for (y = y1; y <= y2; y++)
+        for (x = x1; x <= x2; x++) {
+            lev = &levl[x][y];
+            if (IS_STWALL(lev->typ) || IS_TREE(lev->typ)
+                /* 3.6.2: made iron bars eligible to be flagged nondiggable
+                   (checked by chewing(hack.c) and zap_over_floor(zap.c)) */
+                || lev->typ == IRONBARS)
+                lev->wall_info |= prop;
+        }
 }
 
 STATIC_OVL void