diff --git a/src/elements/O2.c b/src/elements/O2.c
index a8be78b95..2d7aff0aa 100644
--- a/src/elements/O2.c
+++ b/src/elements/O2.c
@@ -30,10 +30,13 @@ int update_O2(UPDATE_FUNC_ARGS)
 					if ((r>>8)>=NPART || !r)
 						continue;
 					if ((r&0xFF)==PT_H2)
+					{
+						part_change_type(r>>8,x+rx,y+ry,PT_WATR);
 						if (50<(rand()/(RAND_MAX/100))) {
 							part_change_type(i,x,y,PT_WATR);
-							part_change_type(r>>8,x+rx,y+ry,PT_WATR);
+							rx = ry = 3;
 						}
+					}
 				}
 	}