diff --git a/doc/fixes3-7-0.txt b/doc/fixes3-7-0.txt
index 8ad654c8c..04c24d09c 100644
--- a/doc/fixes3-7-0.txt
+++ b/doc/fixes3-7-0.txt
@@ -2041,6 +2041,8 @@ priestname() didn't handle "a" vs" "an" prefix correctly; normally priests are
 	incant <scroll>."
 non-fireproof water walking boots wouldn't be burnt up if fire resistant hero
 	walked on molten lava
+1x1 poison gas clouds for green dragon and iron golem breath could be placed
+	at wall locations
 
 
 Fixes to 3.7.0-x Platform and/or Interface Problems Exposed Via git Repository
diff --git a/src/zap.c b/src/zap.c
index 6a83399df..f649436a7 100644
--- a/src/zap.c
+++ b/src/zap.c
@@ -5233,8 +5233,10 @@ zap_over_floor(
 
     case ZT_POISON_GAS:
         /* poison gas with range 1: green dragon/iron golem breath (AD_DRST);
-           caller is placing a series of 1x1 clouds along the zap's path */
-        (void) create_gas_cloud(x, y, 1, 8);
+           caller is placing a series of 1x1 clouds along the zap's path;
+           <x,y> for wall locations might be included--reject those */
+        if (ZAP_POS(lev->typ))
+            (void) create_gas_cloud(x, y, 1, 8);
         break;
 
     case ZT_LIGHTNING: