diff --git a/include/obj.h b/include/obj.h
index f841725ef..ccab26f6e 100644
--- a/include/obj.h
+++ b/include/obj.h
@@ -469,10 +469,12 @@ struct obj {
 #define POTHIT_OTHER_THROW 3 /* propelled by some other means [scatter()] */
 
 /* tracking how an item left your inventory via how_lost field */
-#define LOST_NONE    0 /* still in inventory, or method not covered below */
-#define LOST_THROWN  1 /* thrown or fired by the hero */
-#define LOST_DROPPED 2 /* dropped or tipped out of a container by the hero */
-#define LOST_STOLEN  3 /* stolen from hero's inventory by a monster */
+#define LOST_NONE      0 /* still in inventory, or method not covered below */
+#define LOST_THROWN    1 /* thrown or fired by the hero */
+#define LOST_DROPPED   2 /* dropped or tipped out of a container by the hero */
+#define LOST_STOLEN    3 /* stolen from hero's inventory by a monster */
+#define LOSTOVERRIDEMASK 0x3
+#define LOST_EXPLODING 4 /* the object is exploding (i.e. POT_OIL) */
 
 /* tracking how a name got acquired by an object in named_how field */
 #define NAMED_PLAIN 0 /* nothing special, typical naming */
diff --git a/src/explode.c b/src/explode.c
index 18bf8d53c..36c3aca59 100644
--- a/src/explode.c
+++ b/src/explode.c
@@ -976,6 +976,7 @@ explode_oil(struct obj *obj, coordxy x, coordxy y)
     if (!obj->lamplit)
         impossible("exploding unlit oil");
     end_burn(obj, TRUE);
+    obj->how_lost = LOST_EXPLODING;
     splatter_burning_oil(x, y, diluted_oil);
 }
 
diff --git a/src/invent.c b/src/invent.c
index 6f2cc2528..c3e46faad 100644
--- a/src/invent.c
+++ b/src/invent.c
@@ -4943,6 +4943,8 @@ mergable(
 
     if (obj->cursed != otmp->cursed || obj->blessed != otmp->blessed)
         return FALSE;
+    if ((obj->how_lost & LOSTOVERRIDEMASK) != 0)
+        return FALSE;
 #if 0   /* don't require 'bypass' to match; that results in items dropped
          * via 'D' not stacking with compatible items already on the floor;
          * caller who wants that behavior should use 'nomerge' instead */
diff --git a/src/pickup.c b/src/pickup.c
index a1c2ccb78..a01283cde 100644
--- a/src/pickup.c
+++ b/src/pickup.c
@@ -950,6 +950,8 @@ autopick_testobj(struct obj *otmp, boolean calc_costly)
         return TRUE;
     if (flags.nopick_dropped && otmp->how_lost == LOST_DROPPED)
         return FALSE;
+    if (otmp->how_lost == LOST_EXPLODING)
+        return FALSE;
 
     /* check for pickup_types */
     pickit = (!*otypes || strchr(otypes, otmp->oclass));
@@ -1866,7 +1868,7 @@ pickup_object(
        couldn't pick up a thrown, stolen, or dropped item that was split
        off from a carried stack even while still carrying the rest of the
        stack unless we have at least one free slot available */
-    obj->how_lost = LOST_NONE; /* affects merge_choice() */
+    obj->how_lost &= ~LOSTOVERRIDEMASK;  /* affects merge_choice() */
     res = lift_object(obj, (struct obj *) 0, &count, telekinesis);
     obj->how_lost = save_how_lost; /* even when res > 0,
                                     * in case we call splitobj() below */
@@ -1879,7 +1881,7 @@ pickup_object(
     if (obj->quan != count && obj->otyp != LOADSTONE)
         obj = splitobj(obj, count);
 
-    obj->how_lost = LOST_NONE;
+    obj->how_lost &= ~LOSTOVERRIDEMASK;
     obj = pick_obj(obj);
 
     if (uwep && uwep == obj)