diff --git a/include/extern.h b/include/extern.h
index 28680c5fa..971971ea8 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1158,6 +1158,7 @@ E boolean FDECL(bad_location, (XCHAR_P,XCHAR_P,XCHAR_P,XCHAR_P,XCHAR_P,XCHAR_P))
 E void FDECL(place_lregion, (XCHAR_P,XCHAR_P,XCHAR_P,XCHAR_P,
 			     XCHAR_P,XCHAR_P,XCHAR_P,XCHAR_P,
 			     XCHAR_P,d_level *));
+E void NDECL(fumaroles);
 E void NDECL(movebubbles);
 E void NDECL(water_friction);
 E void FDECL(save_waterlevel, (int,int));
diff --git a/include/rm.h b/include/rm.h
index 00f0bc4c5..cfc399300 100644
--- a/include/rm.h
+++ b/include/rm.h
@@ -189,34 +189,35 @@
 #define S_ss2		72
 #define S_ss3		73
 #define S_ss4		74
+#define S_poisoncloud	75
 
 /* The 8 swallow symbols.  Do NOT separate.  To change order or add, see */
 /* the function swallow_to_glyph() in display.c.			 */
-#define S_sw_tl		75	/* swallow top left [1]			*/
-#define S_sw_tc		76	/* swallow top center [2]	Order:	*/
-#define S_sw_tr		77	/* swallow top right [3]		*/
-#define S_sw_ml		78	/* swallow middle left [4]	1 2 3	*/
-#define S_sw_mr		79	/* swallow middle right [6]	4 5 6	*/
-#define S_sw_bl		80	/* swallow bottom left [7]	7 8 9	*/
-#define S_sw_bc		81	/* swallow bottom center [8]		*/
-#define S_sw_br		82	/* swallow bottom right [9]		*/
+#define S_sw_tl		76	/* swallow top left [1]			*/
+#define S_sw_tc		77	/* swallow top center [2]	Order:	*/
+#define S_sw_tr		78	/* swallow top right [3]		*/
+#define S_sw_ml		79	/* swallow middle left [4]	1 2 3	*/
+#define S_sw_mr		80	/* swallow middle right [6]	4 5 6	*/
+#define S_sw_bl		81	/* swallow bottom left [7]	7 8 9	*/
+#define S_sw_bc		82	/* swallow bottom center [8]		*/
+#define S_sw_br		83	/* swallow bottom right [9]		*/
 
-#define S_explode1	83	/* explosion top left			*/
-#define S_explode2	84	/* explosion top center			*/
-#define S_explode3	85	/* explosion top right		 Ex.	*/
-#define S_explode4	86	/* explosion middle left		*/
-#define S_explode5	87	/* explosion middle center	 /-\	*/
-#define S_explode6	88	/* explosion middle right	 |@|	*/
-#define S_explode7	89	/* explosion bottom left	 \-/	*/
-#define S_explode8	90	/* explosion bottom center		*/
-#define S_explode9	91	/* explosion bottom right		*/
+#define S_explode1	84	/* explosion top left			*/
+#define S_explode2	85	/* explosion top center			*/
+#define S_explode3	86	/* explosion top right		 Ex.	*/
+#define S_explode4	87	/* explosion middle left		*/
+#define S_explode5	88	/* explosion middle center	 /-\	*/
+#define S_explode6	89	/* explosion middle right	 |@|	*/
+#define S_explode7	90	/* explosion bottom left	 \-/	*/
+#define S_explode8	91	/* explosion bottom center		*/
+#define S_explode9	92	/* explosion bottom right		*/
 
 /* end effects */
 
-#define MAXPCHARS	92	/* maximum number of mapped characters */
+#define MAXPCHARS	93	/* maximum number of mapped characters */
 #define MAXDCHARS	41	/* maximum of mapped dungeon characters */
 #define MAXTCHARS	22	/* maximum of mapped trap characters */
-#define MAXECHARS	29	/* maximum of mapped effects characters */
+#define MAXECHARS	30	/* maximum of mapped effects characters */
 #define MAXEXPCHARS	9	/* number of explosion characters */
 
 struct symdef {
diff --git a/src/allmain.c b/src/allmain.c
index 5f5ab44c7..981358e77 100644
--- a/src/allmain.c
+++ b/src/allmain.c
@@ -294,6 +294,8 @@ boolean resuming;
 		    /* underwater and waterlevel vision are done here */
 		    if (Is_waterlevel(&u.uz) || Is_airlevel(&u.uz))
 			movebubbles();
+		    else if (Is_firelevel(&u.uz))
+			fumaroles();
 		    else if (Underwater)
 			under_water(0);
 		    /* vision while buried done here */
diff --git a/src/display.c b/src/display.c
index 0e8b042a6..87658aefa 100644
--- a/src/display.c
+++ b/src/display.c
@@ -674,7 +674,12 @@ newsym(x,y)
 	 */
 	lev->waslit = (lev->lit!=0);	/* remember lit condition */
 
-	if (reg != NULL && ACCESSIBLE(lev->typ)) {
+	/* normal region shown only on accessible positions, but poison clouds
+	 * also shown above lava, pools and moats.
+	 */
+	if (reg != NULL && (ACCESSIBLE(lev->typ) ||
+		(reg->glyph == cmap_to_glyph(S_poisoncloud) &&
+		 (lev->typ == LAVAPOOL || lev->typ == POOL || lev->typ == MOAT)))) {
 	    show_region(reg,x,y);
 	    return;
 	}
diff --git a/src/do.c b/src/do.c
index eae360425..acc241a90 100644
--- a/src/do.c
+++ b/src/do.c
@@ -1288,6 +1288,8 @@ boolean at_stairs, falling, portal;
 	/* initial movement of bubbles just before vision_recalc */
 	if (Is_waterlevel(&u.uz) || Is_airlevel(&u.uz))
 		movebubbles();
+	else if (Is_firelevel(&u.uz))
+	    fumaroles();
 
 	if (level_info[new_ledger].flags & FORGOTTEN) {
 	    forget_map(ALL_MAP);	/* forget the map */
diff --git a/src/drawing.c b/src/drawing.c
index a5cc10d46..a08a7acc5 100644
--- a/src/drawing.c
+++ b/src/drawing.c
@@ -211,6 +211,7 @@ const struct symdef defsyms[MAXPCHARS] = {
 	{'#', "",		C(HI_ZAP)},
 	{'@', "",		C(HI_ZAP)},
 	{'*', "",		C(HI_ZAP)},
+	{'#', "poison cloud",	C(CLR_BRIGHT_GREEN)},	/* [part of] a poison cloud */
 	{'/', "",		C(CLR_GREEN)},	/* swallow top left	*/
 	{'-', "",		C(CLR_GREEN)},	/* swallow top center	*/
 	{'\\', "",		C(CLR_GREEN)},	/* swallow top right	*/
@@ -614,6 +615,7 @@ struct symparse loadsyms[] = {
 	{SYM_PCHAR, S_hcdbridge, "S_hcdbridge"},
 	{SYM_PCHAR, S_air, "S_air"},
 	{SYM_PCHAR, S_cloud, "S_cloud"},
+	{SYM_PCHAR, S_poisoncloud, "S_poisoncloud"},
 	{SYM_PCHAR, S_water, "S_water"},
 	{SYM_PCHAR, S_arrow_trap, "S_arrow_trap"},
 	{SYM_PCHAR, S_dart_trap, "S_dart_trap"},
diff --git a/src/mkmaze.c b/src/mkmaze.c
index 8a5b9b793..d9515de2d 100644
--- a/src/mkmaze.c
+++ b/src/mkmaze.c
@@ -879,6 +879,26 @@ register xchar x, y, todnum, todlevel;
 	return;
 }
 
+void
+fumaroles()
+{
+    xchar n;
+    boolean snd = FALSE, loud = FALSE;
+    for (n = rn2(3)+2; n; n--) {
+	xchar x = rn1(COLNO-4,3);
+	xchar y = rn1(ROWNO-4,3);
+	struct trap *ttmp = t_at(x,y);
+	if (levl[x][y].typ == LAVAPOOL) {
+	    NhRegion *r = create_gas_cloud(x,y, 4+rn2(5), rn1(10,5));
+	    clear_heros_fault(r);
+	    snd = TRUE;
+	    if (distu(x,y) < 15) loud = TRUE;
+	}
+    }
+    if (snd && !Deaf)
+	Norep("You hear a %swhoosh!", loud ? "loud " : "");
+}
+
 /*
  * Special waterlevel stuff in endgame (TH).
  *
diff --git a/src/region.c b/src/region.c
index 562747948..bd47b7949 100644
--- a/src/region.c
+++ b/src/region.c
@@ -996,7 +996,7 @@ int damage;
     cloud->arg = zeroany;
     cloud->arg.a_int = damage;
     cloud->visible = TRUE;
-    cloud->glyph = cmap_to_glyph(S_cloud);
+    cloud->glyph = cmap_to_glyph(damage ? S_poisoncloud : S_cloud);
     add_region(cloud);
     return cloud;
 }
diff --git a/win/share/other.txt b/win/share/other.txt
index 14ec940d5..61258f290 100644
--- a/win/share/other.txt
+++ b/win/share/other.txt
@@ -1439,6 +1439,25 @@ P = (108, 145, 182)
   MMMMMNNNNNMMMMMM
   MMMMMMMMMMMMMMMM
 }
+# tile 75 (poison cloud)
+{
+  BBBBBBBBBBBBBBBB
+  BBBBBFFFFFFFBBBB
+  BBBFFFFFFFFFFBBB
+  BBFFFFFFFFFGFFBB
+  BBFFFFFFFFFFFFFB
+  BFFFFFFFFFFFFGFB
+  FFFGFFFFFFFFGFFF
+  FFFFFFFFFFGGFFFF
+  FFFFFFFFFFFFFGFF
+  FFGGFFFFFFFGGFFG
+  FFFFFGGGGGFFFFGG
+  BGFFFFFFFFFFGGGB
+  BBGGGFFFFGGGGGGB
+  BBBGGGGGGGGGGBBB
+  BBBBBBGGGGBBBBBB
+  BBBBBBBBBBBBBBBB
+}
 # tile 75 (cmap 75)
 {
   AAAAAAADDDDDDAAA