diff --git a/doc/Guidebook.mn b/doc/Guidebook.mn
index e4aec2f8d..9472d54b1 100644
--- a/doc/Guidebook.mn
+++ b/doc/Guidebook.mn
@@ -46,7 +46,7 @@
 .ds f0 \*(vr
 .ds f1 \" empty
 .\"DO NOT REMOVE NH_DATESUB .ds f2 DATE(%B %-d, %Y)
-.ds f2 July 29, 2024
+.ds f2 August 11, 2024
 .
 .\" A note on some special characters:
 .\" \(lq = left double quote
@@ -1696,6 +1696,9 @@ In normal play you can view the explored portion of the current level's
 map without monsters; without monsters and objects; or without monsters,
 objects, and traps.
 .lp ""
+If there are visible clouds of gas in view, they are treated like traps
+when deciding whether to show them or the floor underneath them.
+.lp ""
 In explore mode, you can choose to view the full map rather than just
 its explored portion.
 In debug mode there are additional choices.
@@ -4323,7 +4326,8 @@ symbols for the various object types.
 Any omitted types are filled in at the end from the previous order.
 .lp paranoid_confirmation
 A space separated list of specific situations where alternate
-prompting is desired.  The default is \(lqparanoid_confirmation:pray swim trap\(rq.
+prompting is desired.
+The default is \(lqparanoid_confirmation:pray swim trap\(rq.
 .PS Were-change
 .PL Confirm
 for any prompts which are set to require \(lqyes\(rq rather than \(oqy\(cq,
@@ -4357,6 +4361,8 @@ than immediately praying; on by default;
 .PL trap
 require \(oqy\(cq to confirm an attempt to move into or onto a known trap,
 unless doing so is considered to be harmless;
+when enabled, this confirmation is also used for moving into visible
+gas cloud regions;
 (to require \(lqyes\(rq rather than just \(oqy\(cq, set Confirm too);
 confirmation can be skipped by using the \(oq\f(CRm\fP\(cq movement prefix;
 .PL swim
@@ -4373,7 +4379,7 @@ commands even when wearing just one applicable item;
 .PL all
 turn on all of the above.
 .PE
-By default, the pray and swim choices are enabled, the others disabled.
+By default, the pray, swim, and trap choices are enabled, the others disabled.
 To disable them without setting
 any of the other choices, use \f(CRparanoid_confirmation:none\fP.
 To keep them enabled while setting any of the others, you can
diff --git a/doc/Guidebook.tex b/doc/Guidebook.tex
index 5d66c9c1c..6524dd281 100644
--- a/doc/Guidebook.tex
+++ b/doc/Guidebook.tex
@@ -48,7 +48,7 @@
 \author{Original version - Eric S. Raymond\\
 (Edited and expanded for 3.7.0 by Mike Stephenson and others)}
 %DO NOT REMOVE NH_DATESUB \date{DATE(%B %-d, %Y)}
-\date{July 29, 2024}
+\date{August 11, 2024}
 
 \maketitle
 
@@ -1804,6 +1804,9 @@ In normal play you can view the explored portion of the current level's
 map without monsters; without monsters and objects; or without monsters,
 objects, and traps.\\
 %.lp ""
+If there are visible clouds of gas in view, they are treated like traps
+when deciding whether to show them or the floor underneath them.\\
+%.lp ""
 In explore mode, you can choose to view the full map rather than just
 its explored portion.
 In debug mode there are additional choices.\\
@@ -4752,6 +4755,8 @@ than immediately praying; on by default;
 \item[{\tt trap~~~}]
 require `{\tt y}' to confirm an attempt to move into or onto a known trap,
 unless doing so is considered to be harmless;
+when enabled, this confirmation is also used for moving into visible
+gas cloud regions;
 (to require ``yes'' rather than just `y', set Confirm too);
 confirmation can be skipped by using the `{\tt m}' movement prefix;
 \item[{\tt swim~~~}]
@@ -4770,7 +4775,7 @@ turn on all of the above.
 \elist
 %.ei
 %.ed
-By default, the pray and swim choices are enabled, the others disabled.
+By default, the pray, swim, and trap choices are enabled, the others disabled.
 To disable them without setting
 any of the other choices, use ``{\it paranoid\verb+_+confirmation:none}''.
 To keep them enabled while setting any of the others, you can
diff --git a/doc/fixes3-7-0.txt b/doc/fixes3-7-0.txt
index 372527e9c..88a089184 100644
--- a/doc/fixes3-7-0.txt
+++ b/doc/fixes3-7-0.txt
@@ -1,4 +1,4 @@
-NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1457 $ $NHDT-Date: 1721684298 2024/07/22 21:38:18 $
+NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1460 $ $NHDT-Date: 1723410638 2024/08/11 21:10:38 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -2546,6 +2546,8 @@ paranoid_confirm:swim to prevent accidental dunking into dangerous liquids;
 paranoid_confirm:trap to confirm entering a known trap unless it is harmless;
 	like revised paranoid_confirm:pray, requires y/n response; add
 	paranoid_confirm:Confirm to require yes/no instead
+extend 'paranoid_confirm:trap' to request confirmation when entering visible
+	gas cloud regions
 paranoid_confirm:Autoall to confirm picking 'A' in menustyle:Full filter menu
 looking at a monster will indicate whether it is asleep, and waking up a
 	monster yields a message
diff --git a/include/extern.h b/include/extern.h
index 27c308019..62e286f4a 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1,4 +1,4 @@
-/* NetHack 3.7	extern.h	$NHDT-Date: 1722116044 2024/07/27 21:34:04 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1433 $ */
+/* NetHack 3.7	extern.h	$NHDT-Date: 1723410638 2024/08/11 21:10:38 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1434 $ */
 /* Copyright (c) Steve Creps, 1988.                               */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -2574,6 +2574,8 @@ extern boolean in_out_region(coordxy, coordxy);
 extern boolean m_in_out_region(struct monst *, coordxy, coordxy) NONNULLARG1;
 extern void update_player_regions(void);
 extern void update_monster_region(struct monst *) NONNULLARG1;
+extern int reg_damg(NhRegion *) NONNULLARG1;
+extern boolean any_visible_region(void);
 extern NhRegion *visible_region_at(coordxy, coordxy);
 extern void show_region(NhRegion *, coordxy, coordxy) NONNULLARG1;
 extern void save_regions(NHFILE *) NONNULLARG1;
diff --git a/src/hack.c b/src/hack.c
index 8a47f5b69..f59e26eb7 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	hack.c	$NHDT-Date: 1720128165 2024/07/04 21:22:45 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.449 $ */
+/* NetHack 3.7	hack.c	$NHDT-Date: 1723410639 2024/08/11 21:10:39 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.452 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Derek S. Ray, 2015. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -2517,11 +2517,12 @@ domove_core(void)
 {
     struct monst *mtmp;
     struct rm *tmpr;
+    NhRegion *newreg, *oldreg;
     coordxy x, y;
     struct trap *trap = NULL;
     int glyph;
     coordxy chainx = 0, chainy = 0,
-          ballx = 0, bally = 0;         /* ball&chain new positions */
+            ballx = 0, bally = 0;       /* ball&chain new positions */
     int bc_control = 0;                 /* control for ball&chain */
     boolean cause_delay = FALSE,        /* dragging ball will skip a move */
             displaceu = FALSE;          /* involuntary swap */
@@ -2624,10 +2625,14 @@ domove_core(void)
         return;
 
     /* maybe ask player for confirmation before walking into known traps */
-    if (ParanoidTrap && (trap = t_at(x, y)) != 0 && trap->tseen
+    if (ParanoidTrap && !Stunned && !Confusion
+        /* skip if player used 'm' prefix or is moving recklessly */
         && (!svc.context.nopick || svc.context.run)
-        && !Stunned && !Confusion
+        /* check for discovered trap */
+        && (trap = t_at(x, y)) != 0 && trap->tseen
+        /* check whether attempted move will be viable */
         && test_move(u.ux, u.uy, u.dx, u.dy, TEST_MOVE)
+        /* override confirmation if the trap is harmless to the hero */
         && (immune_to_trap(&gy.youmonst, trap->ttyp) != TRAP_CLEARLY_IMMUNE
             /* Hallucination: all traps still show as ^, but the
                hero can't tell what they are, so treat as dangerous */
@@ -2662,6 +2667,33 @@ domove_core(void)
             return;
         }
     }
+    /* treat entering a visible region like entering a trap */
+    if (ParanoidTrap && !Blind && !Stunned && !Confusion && !Hallucination
+        /* skip if player used 'm' prefix or is moving recklessly */
+        && (!svc.context.nopick || svc.context.run)
+        /* check for region(s) */
+        && (newreg = visible_region_at(x, y)) != 0
+        && ((oldreg = visible_region_at(u.ux, u.uy)) == 0
+            /* if moving from one region into another, only ask for
+               confirmation if the one potentially being entered inflicts
+               damage (poison gas) and the one being exited doesn't (vapor) */
+            || (reg_damg(newreg) > 0 && reg_damg(oldreg) == 0))
+        /* check whether attempted move will be viable */
+        && test_move(u.ux, u.uy, u.dx, u.dy, TEST_MOVE)
+        /* we don't override confirmation for poison resistance since the
+           region also hinders hero's vision even if/when no damage is done */
+        ) {
+        char qbuf[QBUFSZ];
+
+        Snprintf(qbuf, sizeof qbuf, "%s into that %s cloud?",
+                 locomotion(gy.youmonst.data, "step"),
+                 (reg_damg(newreg) > 0) ? "poison gas" : "vapor");
+        if (!paranoid_query(ParanoidConfirm, upstart(qbuf))) {
+            nomul(0);
+            svc.context.move = 0;
+            return;
+        }
+    }
 
     if (u.utrap) {
         boolean moved = trapmove(x, y, trap);
diff --git a/src/region.c b/src/region.c
index 43383ea2f..cbabf4885 100644
--- a/src/region.c
+++ b/src/region.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	region.c	$NHDT-Date: 1707462965 2024/02/09 07:16:05 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.89 $ */
+/* NetHack 3.7	region.c	$NHDT-Date: 1723410640 2024/08/11 21:10:40 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.97 $ */
 /* Copyright (c) 1996 by Jean-Christophe Collet  */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -628,6 +628,29 @@ remove_mon_from_regions(struct monst *mon)
 
 #endif /*0*/
 
+/* per-turn damaeg inflicted by visible region; hides details from caller */
+int
+reg_damg(NhRegion *reg)
+{
+    int damg = (!reg->visible || reg->ttl == -2L) ? 0 : reg->arg.a_int;
+
+    return damg;
+}
+
+/* check whether current level has any visible regions */
+boolean
+any_visible_region(void)
+{
+    int i;
+
+    for (i = 0; i < svn.n_regions; i++) {
+        if (!gr.regions[i]->visible || gr.regions[i]->ttl == -2L)
+            continue;
+        return TRUE;
+    }
+    return FALSE;
+}
+
 /*
  * Check if a spot is under a visible region (eg: gas cloud).
  * Returns NULL if not, otherwise returns region.
@@ -666,8 +689,8 @@ save_regions(NHFILE *nhfp)
         goto skip_lots;
     if (nhfp->structlevel) {
         /* timestamp */
-        bwrite(nhfp->fd, (genericptr_t) &svm.moves, sizeof (svm.moves));
-        bwrite(nhfp->fd, (genericptr_t) &svn.n_regions, sizeof (svn.n_regions));
+        bwrite(nhfp->fd, (genericptr_t) &svm.moves, sizeof svm.moves);
+        bwrite(nhfp->fd, (genericptr_t) &svn.n_regions, sizeof svn.n_regions);
     }
     for (i = 0; i < svn.n_regions; i++) {
         r = gr.regions[i];
@@ -747,11 +770,11 @@ rest_regions(NHFILE *nhfp)
         tmstamp = (svm.moves - tmstamp);
 
     if (nhfp->structlevel)
-        mread(nhfp->fd, (genericptr_t) &svn.n_regions, sizeof (svn.n_regions));
+        mread(nhfp->fd, (genericptr_t) &svn.n_regions, sizeof svn.n_regions);
 
     gm.max_regions = svn.n_regions;
     if (svn.n_regions > 0)
-        gr.regions = (NhRegion **) alloc(sizeof (NhRegion *) * svn.n_regions);
+        gr.regions = (NhRegion **) alloc(svn.n_regions * sizeof (NhRegion *));
     for (i = 0; i < svn.n_regions; i++) {
         r = gr.regions[i] = (NhRegion *) alloc(sizeof (NhRegion));
         if (nhfp->structlevel) {